Population Transport Minister

The ship or ships must be designated population transports as a design type

I had the same problem... but then I started using the IRM Mod and my population transports now do what they are meant to

I did mean Pop transport just couldent remeber how it was abreviated in the design types list.

The IRM ministers work very well but with stock and the balllence mod there is an issue with transports not filling up at the location they are built and not filling up from other colonies they might well depopulate by doing so as a result its dificult to get them to work if you start with one home world early in the game some times as that is almost always where you would build them then and the only planet with enough population to fill them.

Stock ministers also sometimes work oddly or not at all if implimented seperatly

I have the same problem (Demo version).
Just one star system, two planets with same (foreign, migrated) population and atmosphere.
One full, one only 20% filled.
Two transporters of population transport type, minister control enabled, ministers manage population transports.

The ships just did sit there and do nothing. I had to move the population manually.