Just experienced it now:
Aug 16 08:24:44 turris kernel: [1652238.074278] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
Aug 16 08:24:44 turris kernel: [1652238.226830] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
Aug 16 08:24:44 turris kernel: [1652238.379401] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
Aug 16 08:24:44 turris kernel: [1652238.531967] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
Aug 16 08:24:44 turris kernel: [1652238.684533] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
Aug 16 08:24:44 turris kernel: [1652238.837100] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
Aug 16 08:24:44 turris kernel: [1652238.989667] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
Aug 16 08:24:45 turris kernel: [1652239.142248] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
Aug 16 08:24:45 turris kernel: [1652239.294800] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
Aug 16 08:24:45 turris kernel: [1652239.447369] ath10k_pci 0000:02:00.0: SWBA overrun on vdev 0, skipped old beacon
Aug 16 08:24:46 turris kernel: [1652241.030330] ieee80211 phy0: Hardware restart was requested
Aug 16 08:24:48 turris kernel: [1652242.391526] ath10k_pci 0000:02:00.0: device successfully recovered
Default ath10k driver - only 5Ghz card inside the router, the 2.4 card had bad reception anyway.