Not all memory in PS-3 was reset with factory DCS reset. So wrt motion, you can have an engine locked in neutral conventionally and run fine in DCS. So conventional reset or unlock procedure. It is not an adding to DCS locks it out issue. G
I respect your opinion and experience, but it's an easily repeatable test.
Take one of these known problem engines ( I gave a list of two and I have more than one example of the ES44 Freedom Diesel https://www.mthtrains.com/30-20433-1), test run under conventional- proving it's not locked out.
Then the only step you take is adding to a DCS system (remote or app) using the add engine command.
Then attempt to run conventional and NOW conventional is locked out.
I agree that this should not happen and this is not "normal" and there are tons and tons of engines in my collection that do not have this behavior. However, some of the first engines I ever bought did lock out, and caused me a fair amount of grief at the time with the club not having DCS but me having DCS at home.
And, I just spent 10 minutes testing this methodically with that exact engine 30-20433-1. Engine was run under conventional with no DCS connected to the track. Ran fine. Connected DCS TIU, powered track, added to a fresh completely reset DCS remote. Started up the engine under DCS, only commands were startup, checking forward and reverse movement, then shutdown. Removed TIU and DCS from track. Attempted conventional- engine was locked out and would not move under conventional and multiple attempts. Power using Z4000.