What year is the bike?
I don't think I have seen dash lights completely out, but I have seen both signal indicators dimly lit and high beam indicator light on. This happened on my '07 at a stop on a hot day. Went away but came back a few days later. I didn't have other symptoms - glove box solenoid, windshield mechanism, failure to start etc. (Possible that my dash lights were out, but I didn't notice in daylight...)
Mine was S6 (S4 was dealt with by recall). Easily fixed.
Read
@rbentnail post on spider repair...
https://www.fjrforum.com/threads/my-spider-bite-story.170085/
I don't bother with a battery tender during winter storage. I do, however, give the battery a quick "top-off" charge a couple of times over the winter. The FJR normally has a very low parasitic draw (less than 1 milliampere) and a healthy AGM battery shouldn't self-discharge more than maybe 5% per month. Still, a properly functioning and temperature compensated battery maintainer shouldn't hurt. 12 years and 160,000 km on my 2011 OEM battery with no tender. I have seen a "bad" tender overcharge and "cook" a battery.
Note: "Float" voltage varies as a function of temperature. Higher voltage is required at lower temperatures to maintain full charge (opposite for high temperatures). Higher quality battery maintainers adjust output for ambient temperature.
My FJR hasn't been ridden in nearly a month - tires need changing and I haven't gotten around to it. The BMW F700GS has seen some action. As of yesterday, I think I am done for the season. I need to make sure tank is topped off, add some stabilizer and run the engine until fully warmed up - usually until the fans come on.