On a few occasions, some sMerit TX were rolled back by the Admin, due to Merit abuse or being sent from a hacked account.

As far as I can recall, once or twice the TXs were deleted, whilst of a few more occasions, TXs with negative value were inserted into the system to counter the positive TX.

See negative TX values here for example (top of left list):
https://public.tableau.com/shared/8KFYY9SSY?:display_count=n&:origin=viz_share_link