Web ui change history

Hello all,

We have a weird scenario where in the Change history of a service contract, Partner Function: Contact person was deleted for several persons on the same time e.g. 11.10 a.m.and there are around 300 deletions recorded in the same minute.

Just wanted to know how to tract down this issue, since the user is denying for making any change. I have checked the CDHDR table and the entries exist.

What could be the possible reason for this issue, where to look?

Thanks,

Pradeep