I went back to my map and recreated the Burrow/Unburrow that you used and I still get the same result, one of my air units being unable to move.
Well, now you know the issue is not the morph ability itself, since I presented you a morph ability that works, so you should replicate the same parameters of the morph ability I did, if you are having issues with the custom unit you previously had, you could create two new banshees from scratch, replicate my morph abilities, give them the abilities, make sure that it works, then begin adjusting the new unit to resemble your former custom unit little by little, then, if after making some modifications you see the morph ability ceases to work, you'll know you're screwing something up. Either way this is as far as I go, now is up to you to figure it out, good luck.
I don't know what you are doing, but you are doing something wrong, I have an old map that I used to test imported models, I went there duplicated a banshee twice, named one copy Banshee A and the other Banshee B, I gave Banshee A a height of 0.7, then gave Banshee B a Height of 5, I duplicated the Zergling Burrow and Unburrow abilitties, renamed them to Morph A and Morph B, I changed the parameters of Morph A to transform the unit that uses the ability to Banshee B, then I changed the parameters of Morph B to transform the unit that uses the ability to Banshee A, then I gave Morph A to Banshee A and Morph B to Banshee B, I tested them in game and it works flawlessly, I uploaded the map to a file sharing site (link below), you can download it and see for yourself if you want.
Ok I checked the Zeus lift off / land ability, those are two morph abilities, lift off is morph ability and land is a morph placement ability, and you have to check the "flags" parameter for both abilities, there is a bunch of modifiers in the flags field, one is suppress movement, I think this modifiers are only supposed to last while morphing from one unit to another, but maybe it you have supress movement checked in one of the morph abilities, it might be affecting the morphed unit, leaving it unable to move. The other thing is that each of the morph units should have one of the morphed abilities (land or lift off) and in each morph ability you should have the correct unit reference or the morph abilitty might get screwed. You should check all these things and see if you can find the problem. Also you could use the viking's Assault and Fighter as your morph abilities as the base, which both are regular morph abilities, I have used that one as the base ability for my morph abilities and never experienced a problem. Maybe using the morph placement ability is part of the issue, but it has been a long time since I used morph abilities in one of my maps so who knows.
You don't provide enough information to really understand what's going on, but if you want to make a unit change it's height you don't need to use the morph ability you can use any ability that grants a unit a buff type behavior, then create a buff type behavior and within the behavior go to modifications/Unit, there you can modify the "height time" parameter, to set the time that takes the unit to move to a new height and set the "height" parameter to whatever height you want the unit to have after aquiring the behavior. You can use a behavior type ability to allow you to toggle on and off the height adjusting behavior. If you want to check an ability within the editor that changes the height of units, you can change kerrigan's "crushing grip" ability, to view the ability your map needs the swarm campaign dependencies added/enabled.
Well, now you know the issue is not the morph ability itself, since I presented you a morph ability that works, so you should replicate the same parameters of the morph ability I did, if you are having issues with the custom unit you previously had, you could create two new banshees from scratch, replicate my morph abilities, give them the abilities, make sure that it works, then begin adjusting the new unit to resemble your former custom unit little by little, then, if after making some modifications you see the morph ability ceases to work, you'll know you're screwing something up. Either way this is as far as I go, now is up to you to figure it out, good luck.
I don't know what you are doing, but you are doing something wrong, I have an old map that I used to test imported models, I went there duplicated a banshee twice, named one copy Banshee A and the other Banshee B, I gave Banshee A a height of 0.7, then gave Banshee B a Height of 5, I duplicated the Zergling Burrow and Unburrow abilitties, renamed them to Morph A and Morph B, I changed the parameters of Morph A to transform the unit that uses the ability to Banshee B, then I changed the parameters of Morph B to transform the unit that uses the ability to Banshee A, then I gave Morph A to Banshee A and Morph B to Banshee B, I tested them in game and it works flawlessly, I uploaded the map to a file sharing site (link below), you can download it and see for yourself if you want.
link:
https://ydray.com/get/t/16811770970804BdMAd68ce1c6d899bB
Ok, then use the zergling burrow / unburrow instead.
Ok I checked the Zeus lift off / land ability, those are two morph abilities, lift off is morph ability and land is a morph placement ability, and you have to check the "flags" parameter for both abilities, there is a bunch of modifiers in the flags field, one is suppress movement, I think this modifiers are only supposed to last while morphing from one unit to another, but maybe it you have supress movement checked in one of the morph abilities, it might be affecting the morphed unit, leaving it unable to move. The other thing is that each of the morph units should have one of the morphed abilities (land or lift off) and in each morph ability you should have the correct unit reference or the morph abilitty might get screwed. You should check all these things and see if you can find the problem. Also you could use the viking's Assault and Fighter as your morph abilities as the base, which both are regular morph abilities, I have used that one as the base ability for my morph abilities and never experienced a problem. Maybe using the morph placement ability is part of the issue, but it has been a long time since I used morph abilities in one of my maps so who knows.
You don't provide enough information to really understand what's going on, but if you want to make a unit change it's height you don't need to use the morph ability you can use any ability that grants a unit a buff type behavior, then create a buff type behavior and within the behavior go to modifications/Unit, there you can modify the "height time" parameter, to set the time that takes the unit to move to a new height and set the "height" parameter to whatever height you want the unit to have after aquiring the behavior. You can use a behavior type ability to allow you to toggle on and off the height adjusting behavior. If you want to check an ability within the editor that changes the height of units, you can change kerrigan's "crushing grip" ability, to view the ability your map needs the swarm campaign dependencies added/enabled.