Issue
- 11 days after boot - all devices are kicked from 5ghz networks (PCs, phones, etc)
- 5ghz SSIDs showing but devices can't reconnect
- 2ghz continues to work fine, 2ghz devices don't show any issues and can reconnect if necessary

- eap system log doesn't show anything useful

Workaround
Working: Toggling 5ghz off then back on in UI fixes the problem (for another x days).

Not Working: Using the scheduler to turn turn radio off then back on 1 minute later does not fix the problem. This option doesn't allow selecting 2ghz or 5ghz radios, assuming it applies to both.

Network Settings
2ghz settings: b/g/n, 20/40mhz, channel 1, 24dbm, balancing off, fairness off, interval/period/thresolds default (100/1/2347/2346)
2ghz networks: 4x2ghz - network 1 no vlan, network 2 vlan 4, network 3 vlan 4, network 4 vlan 3

5ghz settings: a/n/ac 20/40/80mhz, channel 149, 24dbm, balancing off, fairness off, interval/period/thresolds default (100/1/2347/2346)
5ghz networks: 2x5ghz - network 1 no vlan, network 2 vlan 4

All - WPA Personal / WPA2-PSK / AES, Group key update interval 0

Other Settings
no controller, single unit
no portal
no mac filtering
no schedule
band steering off
for both 2ghz and 5ghz - qos defaults, noack off, unscheduled auto power save off
rogue detection off

syslog enabled to a local server

Testing Status

test 1 - 5.0.3 Build 20210604 Rel. 51934 - issue present at uptime showing 11d

test 2 - 5.0.2 Build 20210303 Rel. 34713 - issue present at uptime showing 11d

test 3 - 5.0.1 Build 20201224 Rel. 59228 - no issues - uptime of 23 days

test 4 - 5.0.4 Build 20211021 Rel. 57494 - issue present at uptime showing 11d - reverting to 5.0.1 for test 5

test 5 - 5.0.1 Build 20201224 Rel. 59228 - issue present at uptime showing 29d - continuing to see if it happens again

It looks like this issue takes much longer to appear on 5.0.1. Also if it is left alone, after 15 minutes or so 5ghz starts working again, so it is possible that this happens more frequently but is not noticed.

not tested yet:
5.0.0 Build 20200918 Rel. 161625
2.21.0 Build 20200522 Rel. 49688
2.20.0 Build 20200423 Rel. 36779

Notes
- In 5.0.0 release notes there was one point: "4. Fixed the bug that the 5G client may not be able to associate after working for a long time (>50d)." - This appears to describe my issue except I see it after 11 days.

- This issue is never permanent, it will always get fixed after toggling 5ghz enabled on/off or if I cycle the unit's power.

I will update this post in 15+ days to see how long 5.0.1 stays stable. No AP settings have changed.