maybe #4628 again?

[eddie5]

Player's reputation can go below 0 with modreputation (as of Dec 5 nightly), vanilla won't go negative this way (I haven't tried directly setting it to <0).

[akortunov]

Not quite. That bug was about data loading from ESM - OpenMW could not load values in the [128; 255] range properly.

[eddie5]

Just saw 'should be unsigned' & figured that'd explain it. Thx.