But why with only 552 activities? Any specific reason?
It's because they had reached already the minimum activity required to become Legendary, which is between 775-1030 activity, i should have specified this before.
Anyway activity can be reduced by deleting posts i think this may be the case.
That's what I said. There were not huge deleted posts for 6 users who got 1000 merits while their activity is not between 775-1030. I think you missed my point. This user got 1000 merits while he has only 552 activities. 4 users got less than 775 activities but more than 700 and another got for 600+ activities.
From BPIP, no modlog is there for Rollin.io, for the rest, the maximum deleted posts are 2 only.