I think I know what is going on here.
The charge controllers are doing their mode selection based on battery voltage as they should for the proper top of charge. But when you do not get enough solar to top up the batteries, it falls short of a full charge. Maybe you did get to only 85% charge, so the voltage never reached the point where it would go to absorb mode. The charge controllers did all they could with the available solar energy.
The problem here is that the Batt Mon does not know that it didn't reach full charge. It saw the charge current fall off, so it assumes you did reach a full charge, so it reset the capacity meter back to 100%. There are settings for how sensitive the auto reset is in the Batt Mon. The voltage has to be above a certain setting, and the current has to fall below a certain setting. If it sees both happen, it thinks the battery is full, and resets to 100%. The good news is this should have no effect on the charge controllers, as they should still be looking for the correct full charge voltage to switch into absorb mode. But since it did reset to 100% at a lower state of charge, you now see it it this lower 100% before the batteries are really full.
The bad news is, with not enough sun, each day, you are pulling your battery bank lower and lower. At some point, the battery monitor will stop resetting as the voltage is just too low. Check your voltage and see where you are. With LFP cells, it is not as obvious, but if you are getting down to the lower knee, you know you have an issue. You may very well need to run the generator to get back to a true full charge state if you don't start getting some good sun soon. If you have grid power available, you could just force a bulk charge on the XW-Pro and get topped up. A bit on the electric bill is better than depleting your batteries. But if you are fully off grid, you need to either get the generator happy, or reduce you loads so the sun can keep up for a few days. During my grid failure, I resorted to my generator powering a basic 600 watt charger to pump a little power into my battery bank. That eliminated the XW having to qualify the power. I ran that for about 2.5 hours, pushing about 1.5 KWHs back into the batteries. That was not a huge help, but it was better than nothing, and my refrigerator also ran off the generator during that 2.5 hours, taking that load off of the battery bank.
I just pulled up the Battery Summary graph in Insight for the day my grid was down. My battery bank was at just 51 volts from running my house the night before, so when the grid went down at 3:19 am, I was already at about 60% SoC. It started pulling 5 to 6 amps from the battery to run the few items I had on the backup panel. I had not moved all the circuits yet. I had to run an extension cord to plug in the fridge. From 7:30 am to noon, you can see the load increasing as I added a few more things to the backup panel. From noon to 1:30 you can see the 3 times I tried to get my generator to connect. It would only hit 7 amps of charge current, and shut down again. So that works out to about 500 watts to loads, plus 350 watts of charging = less than 1,000 watts from the generator and it cut out. That stinks for a 5,000 watt rated gen.
Due to a glitch in the Enphase CA Rule 21 profile, the solar refused to come online as well. Finally at 4:27 pm, Enphase was able to remotely reset my inverters and the solar started charging my system, running all my loads and pushing 400 watts into the battery bank, but this did not last long, as the clouds came back, and then the sun set. But at least it showed the AC coupling was working and I was getting charge power and running on solar during the grid failure. I plugged in the generator with the charger, from a bit after 8 pm, to almost 11 pm, when I figured the neighbors had enough of hearing my generator. That held the battery voltage steady, so it was enough power to run the loads in the house without taking any out of the battery. I stayed running on battery all the way to just before midnight when they grid came back up. I put the XW-Pro into a bulk charge mode, but at just 13 amps to bring the battery bank up a bit over night. The next morning also had decent sun, so it all recovered without a problem. So now, I just need to get motivated and work on the governor on my generator and hopefully make it actually work on the AC2 input. I should be able to charge at over 3,000 watts, not just 600.
