The Mannipulator can only put rockets in the plattform when facing in the middle of the platform.
But this is not possible because it needs a launching panel and a Support frame

That is not a bug. Its actually something that is no longer supported due to how calclavia change the multi block system. it use to be is i could access the multi-block threw UE. Now i can't since the multi-block is part of Calc's lib. What i can do is modify ICBM later down the road to better support interaction with machines threw the multi-block. Right now though i don't have time to work on ICBM and am frankly looking at recoding several parts of it for calc.