Problem creating submodels with Steps using LDCad

[John]

Does it only happen with mpd's or also when using separate ldr files?

I'm not sure how to do this using separate ldr files, so I can't say.

Does it happen when you restart after the split and before adding stepping?

No. It only happens after adding stepping.

Could you post a before and after mpd, maybe I can spot a pattern.

Here you go:
Before
After