Nighthawk AC1900 Model 7000 Smart WiFi Router Random Disconnect

I purchased the Nighthawk AC1900 Model 7000 WiFi Router about 8 months ago, and it performed flawlessly until about three weeks ago.  About once a week, the router seems to disconnect from the cable modem without any associated power failures or interruption in cable service.  My internet access is intact during these episodes, which I verified by connecting my laptop directly with a cable.  When I try to reconnect (which it appears I have to do manually from various iOS devices, as the automatic join is not working during the episode), I get a message that the password to join the network is incorrect.  I've learned that by disconnecting the power to the router and restoring power, the iOS devices reconnect automatically and the password is accepted as usual.

I searched the forum, and found a similar thread back a few years, although the OP seemed to be having this problem much more frequently.  I work from home daily, sometimes with time critical projects, and don't want to be left completely high and dry without a WiFi connection.  Has anyone else had this problem?  Should I replace the router?  Thank you in advance for any advice.