Arf, finally, it is not fixed at all. I have again lost one full evening of play for nothing...
If I dismiss one character and take it back then leave the camp, it works.
Some ideas from where the bug is coming:
- Replace the character by an origin character or an hireling.
- Respec one character origin or hireling
- Move to another area (lower city -> dracosyr road)
EDIT: I made some tests.
Recruiting Origin -> Works
Recruiting Origins + Save -> Works
Recruiting Origins + Travel Other area -> Works
Recruiting Origins + Respec (with and without save) -> Works
Recruiting Origins + Exit The game + Return to game with Continue -> Failed
So, it seems that as soon as you are not exiting the game, you can retrieve characters from the Fletriss piece of furniture without any issue and they will follow you. If you exit the game, you can retrieve the character but it will not follow you (like he think he is controlled by another player). Some link is somehow broken in this case and it is definitive...
Definitly a bug ; I will send my test to Larian for fixing.
As a workaround, before quitting the game, ensure you collect all your custom characters in your party. It should work.