Kathy,
We used to purge caches after table updates all the time — until we discovered afterward that segments inside of xlate iterates got messed up. However, I don’t believe we had the problem with just one message — it would be any message after the purge. When upgrading from 3.5.2 to Platform 5.3, I verified that the problem still occurred, so we simply cycle the processes to avoid the problem. (We haven’t installed any revisions yet, though.)