Diffrence in the book stock between HU IM and WM

Dear Experts

In production we have a Handling Unit for a material XXX with quantity = 100 EA (as I can see in HU02 or HUMO)

IM stock as seen in MMBE also shows 100 EA.

But however, WM stock shows HU having 1ty = 104 EA (as displayed in LS26)

How can this be possible? In what scenarios this can happen?

How can we find out what is the casue for this diffrence in the book stock between HU / IM/ WM?

Pls suggest.

Regards

shetty