I haven't encountered this message earlier. The documentation generally has the most common error and syslog messages. I have not been able to find any specific information about this. So my guess is that it might not be very serious.
However the following troubleshooting document would be helpful :
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...