Since updating to the referenced firmware version, I have experienced constant intermittent drops on devices connected to the 2.4G and 5G frequencies. Connection between Router -> Modem -> ISP is stable with no reported signal loss. When a device drops the connection to the internet, it still shows connected to WIFI but I cannot connect to the default router IP through a web browser or any services outside of my network (websites, apps). Device connection loss lasts ~2 mins until restored.
AX1800 Internal Network Issues
Model: Archer AX1800
Hardware Version: V1
Firmware Version: 1.2.0 Build 20201023 rel.69937(5553)