[0.49.19] Unable to load HQ file from 49.18

[StarColonel]

[0.49.19] Unable to load HQ file from 49.18

[HammerGS]

Duplicate of #4061

fixed for next release.

[BoloNike]

Potentially still duplicate however i did not find any C3i or other "BAP" style items on units that do not have sensors. He had infantry with special training (Engineers) but no abilities

Attaching same campaign file. Curated customs list (pulled only what needed with MUL changed to -1) and logs.

1st_Shadow_Army30570201.cpnx.gz
Necessary.zip

The logs are almost identical except where mine shows "Unknown Source" Rather than a line.

megamek.log
megameklab.log
mekhq.log

Hopefully it is still a duplicate but with not finding any of the "BAP" stuff yall mentioned figured i would send the additional data as i mentioned i would earlier

[Sleet01]

I was able to load the @StarColonel 's campaign in 0.49.19.1, which includes the fix for #4061 , without any other changes.
I'm not sure which unit was not loading correctly, but this indicates strongly that the issue is fixed in 0.49.19.1 and 0.49.20, and likely is caused by the unit reset / BAP-without-sensors handling error.

@BoloNike I'm relatively certain that we do not see any loading bugs caused by incorrect MUL numbers, as the field itself is just a string and only consumed by sort lists and the URL generator in newer versions of MML.
However, I would expect to see issues with refits if the MUL were incorrect as I believe we compare them when deciding if a given variant is a refit option, or just the same unit type, as a given unit - and having the same MUL might cause issues during that check.