You still have failed to provide ALL the following information:
- the airport used ( if it's not default, which scenery was used )
- the gate used
- the airplane used
- the GSX operation that was started
Don't say "the problem is general" or give different examples. Just indicate ONE case with ALL the above data, that can be tested.
Of course, I can see loaders just fine and, more important, nobody else has reported missing loaders so far.