Strange behavior today w/ TWO 200W panels wired in parallel

[TT_Vert]

This is on my RV.

I'm just looking for opinions. The problem is resolved but I'm trying to wrap my head about this as the behavior doesn't make sense. I noticed in my solar app that I was only seeing about 12V fed into my MPPT  controller and no current into the batteries. Battery SOC was near 40% so i knew something was wrong. I have a triron 3210N MPPT and two 200W panels wired in parallel so I should see about 22V and at least SOME current today. I checked my other array for my shed and it was putting out power so i knew I should be seeing something.

I took my DVOM and noticed that when I turned OFF the breaker between the panels and the charge controller I would see 24V from the panels but the second I turned the solar feed back on to the MPPT it dropped to 12V and still no current. Turns out one of my two panels' positive plugs was loose. But given my panels are wired in parallel, shouldn't one panel have still been providing current and 22ish V? Why would this occur when it was loaded only?

Thanks much,

Dave

[thm_w]

Doesn't really make sense unless one panel is bad or was very shaded.
Or the loose connection was not where you thought and affected both panels.

Do a short circuit current comparison between the two maybe?