if they toss back to back that is 1 in 10000 chance my guess is the pool has
bad code
bad server
bad internet
or bad gear mining on it.
Or the pool owner decided to snag a block reward for themselves. I hazily recall a pool getting caught out for the statistical improbability of their never finding extremely lucky blocks back around 2012. Turned out the owners were taking all the blocks the pool found below a certain share threshold.
That falls under bad code , but could be teased out of that slot .
maybe
bad code and or bad pool op.
or two separate spots.
I had a pool with 6 of 10 over 90% and 2 of then 90's were 99 back to back.
I stopped mining there a few years back.