I notice now and then that since LoTv some have problems getting the portrait of certain units to appear correctly, sometimes only smoke will be seen or perhaps no background. I too had that problem, but I found out how to fix it.
First choose "send transmission for player". Be aware that this is located in "general" not "Transmissions". The reason for using this is so we are able to set the "Portrait actor".
I use "Source: Model Transmission Source. For example: Artanis Ex2 Portrait
So now, all you have to do is to set the "portrait actor" to the same name as the "model transmission source" without spaces: ArtanisEx2Portrait.