It takes up to several minutes for such notification tasks as
RebuildNotification to be processed. Because these tasks lock the related record in the Account table, some other tasks/operations requiring lock on the same record fail with
Statement timeout error.
There are lots of resellers on the installation, the issue is caused by the bug with id #PBA-80212 ("Taxes are checked incorrectly when filling the placeholders for ARDoc notifications").
Please contact your Technical Account Manager or a member of Pooled Technical Associates Team to clarify status of the software issue.