I have had this as well recently. I've even had a transaction where points were just added and there was no description at all in the transaction line.
This is my problem - the lack of description in the transaction line. Just adding points and subtracting points.
I have mystery bonus points posting in EDR. However I am not complaining.
I've got the same problem, no description and both adding and subtracting of points, with the net effect of a loss. I can't seem to reconcile either of the amounts. Imagine that on your bank savings account statement! A bit dodgey...