Hi Mike,
Looks like this message is error 12306. I don't find any new bugs related to this message for 16.x.
When the message is output in the log, is it on a line with the usual errorlog prefix
(e.x. "00:0006:00000:00893:2016/04/21 18:45:10.32 kernel ....")?
The fourth field in(00893 in the example above) is the spid of the session that hit the error. if you
have the MDA monitoring tables set up to capture SQL and catch the message being raised quickly enough,
you can look up what that spid was doing at that time in monSysSQLText.
A configured shared memory dump (CSMD) could also be set up on 12306 to figure out the root cause.
-bret