Thanks a lot.
P.S. I've tested with my 8.5.2 client and found the following rules stand.
In a db newly created with a template, all those files have no 'P' flag set.
Once edited, if the db where the element resides inherits design from a template, P flag is set. If the db is template itself and doesn't inherit design from other db, P flag is not set.
Hi Maureen, one more question, per my understanding, only the 8.5.3 designer is needed to fix these issues. The server is not mandated to upgrade. Am I right?