GT-AX6000 AiMesh node WPA group rekeying fails with error -23 (BCME_UNSUPPORTED)

[pdc]

On my GT-AX6000 AiMesh node, I am regularly (every hour) getting this block of errors in the log:

Apr 22 11:45:12 wpa_supplicant[6387]: eth6: WPA: Group rekeying completed with XX:XX:XX:XX:XX:XX [GTK=CCMP]
Apr 22 11:45:12 kernel: kck:
Apr 22 11:45:12 kernel:   0000: ed 22 e0 f8 07 95 68 94 bf 2d e1 45 d6 25 b1 d5
Apr 22 11:45:12 kernel: kek:
Apr 22 11:45:12 kernel:   0000: 9d a5 97 76 92 ff f7 f0 f9 51 91 27 ed 7f b0 2f
Apr 22 11:45:12 kernel: replay_ctr:
Apr 22 11:45:12 kernel:   0000: 00 00 00 00 00 00 00 03
Apr 22 11:45:12 kernel: CFG80211-ERROR) wl_cfg80211_set_rekey_data :
Apr 22 11:45:12 kernel: seting gtk_key_info failed code=-23
Apr 22 11:45:17 wpa_supplicant[6392]: eth7: WPA: Group rekeying completed with XX:XX:XX:XX:XX:XX [GTK=CCMP]
Apr 22 11:45:17 kernel: kck:
Apr 22 11:45:17 kernel:   0000: 80 28 c6 b4 55 d5 41 cb 03 9b 86 f1 61 5b c0 ef
Apr 22 11:45:17 kernel: kek:
Apr 22 11:45:17 kernel:   0000: 95 6f bc 74 25 d8 29 b1 c1 51 d5 8a 7e a2 f8 0e
Apr 22 11:45:17 kernel: replay_ctr:
Apr 22 11:45:17 kernel:   0000: 00 00 00 00 00 00 00 08
Apr 22 11:45:17 kernel: CFG80211-ERROR) wl_cfg80211_set_rekey_data :
Apr 22 11:45:17 kernel: seting gtk_key_info failed code=-23

The AiMesh node uses 5 GHz backhaul, and that part seems to be working okay. The MAC addresses listed in the log are for the 2.4 and 5 GHz wifi interfaces on the main host node, also a GT-AX6000. What I have noticed is that wifi clients, like mobile phones, will get bumped off of wifi for a few minutes. Wired clients using the 5 GHz backhaul do not seem to be affected. The main host node does not have similar errors in its log.

It's strange that it looks like it works, but then it gives the gtk_key failure message, and it does appear to bump wifi clients.

I tried a hard reset of the AiMesh node, and it did not help. I am running the latest Merlin firmware (3006.102.7_2) on both nodes, but since the issue is in the broadcom driver I know it's nothing the Merlin firmware can affect.

Any ideas?