450i - Time Set issue

On 450i’s not using a cmm, we see Time Set messages in the event log occurring every 5 minutes. Switching to ntp as a time source instead of gps seems to alleviate the issue. We are on code revision 16.2.3, though it also happens on our one AP on 16.2.2. Looks like the issue has been occurring for at least a month. We have not made any recent firmware upgrades or hardware upgrades. The issue occurs throughout the area in geographically diverse areas, which leads us to believe it may be satellite related?

Is there any known issue with GPS receiving time with 450i’s when not using a CMM? Could the messages and frequency of the messages have any undesirable impact on the AP?

Yes, there is a known issue with some GPS chips software not always sending the right time to the radio. Because of this, in 16.2.1 it was added a setting:
Configuration → Time → Current System Time → “Allow GPS to set System Time : Enabled/Disabled”.
I recommend using NTP and setting this to Disabled.