Interesting to note is Cisco shows that "It should also be resolved in the 16.3.6 and later builds" - we are running 16.3.7 and the bug was present on at least one 3650.
https://bst.cloudapps.cisco.com/bugsearch/bug/CSCva49947Symptom:A 3650 or 3850 switch that is NOT acting as a WLC and does not have this functionality enabled may throw misleading errors like:*%SOCKET-2-SOCK_RECV_ERR:Switch 1 R0/0: wcm: Error parsing...
