For each pending posts and token, the amount of rshares, distributed by votes is stored in the database. The sum of all pending rshares is stored as bigint in the database.
A bigint has a range up to 9223372036854775807.
Yesterday, a number higher than this was tried to store in the database, as there are currently more pending rshares for the Weed token.
A vote with 1 staked Weed leads to 1e8 rshares, due to the precision of 1e-8.
I have currently only access to my mobile, but I could fix the problem by changing the the type to numeric, which has a variable precision and is still exact.