Yeah thats the same issue.
See Database error: "sql: transaction has already been committed or rolled back" - #52 by tomp for discussion around the fixes. If you can wait then there will be a software fix to make the DB queries more efficient so they don’t time out when instances have lots of snapshots. If not, and you can afford to lose some snapshots, then another approach is to delete some of them manually as per the steps on that thread.