12 Volt reset ??

Not at all unusual find a 12 volt reset will get an inoperable slide to work. It has happened to me before. A different time I lost the ability to read current for L1 on the EMS panel. A reset of the 12 volts and all was well.
I for one need to learn that when 12 volt dc things stop working, a simple hard 12 volt reset is the first thing to do before tearing into the electronics.

X2 on cleaning and dielectric grease.

I would suggest going through your battery connections. Disconnect connections one at a time, clean good, applu coating of electrical grease and reconnect.

Almost everything is computer controlled now so doing a reset is not too unusual. My Monaco coach would occasionally go into limp mode and required a 12 volt reset. This might last for 10-20,000 miles before I had to do it again. The same goes for the occasional check engine light. Just disconnect the battery for a minute or so and see if it pops up again. A lot of times that reset is all it takes. I never had issues with my slide controller but I did have issues with my energy management system. This is possibly what was causing your issues. A reset cured that also. Through the years I have found that my first troubleshooting task for anything that uses electrical power is to remove power and do a reset and see if that corrects the problem.