1. sometimes in the params for the item with the type of 'db monitor' line comes from completely different item (with type 'calculated').
2. after adding the item with type 'db monitor', it goes into a unsupported, due to the fact that the params are not immediately added to the dbcache. similar behavior when you restart the server.
3. large and with many strings SQL queries are cut, tested on a query length of 982 characters. And cut very strange ... I stayed only the first row.

I sent a letter with an attached logom and sampling of the database items.

logs including more debug messages. Patch for thise in attachment.