I am having this same issue. Has been happening for about 2 weeks and nothing in mysetup has changed. I replaced all the batteries, rebooted my modem/wifi router and moved the location of the Ring bridge. The bridge has a green status of -45RSSI which is fairly strong.
I called into the customer service and they told me to re-boot my wifi network, which I had already done without any success in fixing the issue. The 2 pathlights that go off and on the most seem to have moisture in them. I took one apart and cleaned it out, but it has shown up again. I am wondering if that is the reason for the issue?
As I type this I have had the lighs go offline and back on at least twice. Rather annoying.