Lost SNMP response

Very shortly after upgradeing to 7.1.4 all the APs with 40 or more users will lose SNMP response.

47 APs with less than 40 SMs are fine all of the time and have been running for 2 weeks without problems.

5 APs with anywhere from 40 - 62 SMs will lose SNMP within a couple of hours after rebooting them.

Anybody else have this problem??