There was a suggested edit that collided with an edit by the OP. The OP had added information to the question, but the suggested edit was missing this, so in the comparison it was like the edit removed this part.
I wanted to approve the suggested edit and also improve it by re-adding the missing part. Meanwhile, the suggested edit had been rejected by 3 people. As a result, the things changed by the suggested edit are now attributed to me.
Either the suggested edit should have been included in the revision history anyway, or it shouldn't be possible for 3 people to reject it while someone else is improving it.
(The question has also been removed now, so it's 10k+ to view it I believe)