Just butting in here. From my understanding, our arc fault detection monitors the PV current and voltage waveforms. It is constantly monitored to see if there is a waveform pattern that matches the pattern of a typical arc fault. If it sees this pattern you will get an F63 arc fault on the Sol-Ark. I believe this is also how most arc fault detection works on other safety products as well because detecting arcing( to open air, wood, other wires ect.) is historically pretty hard. This is just what I have heard by no means can I confirm this as a 100% certainty, but I have no reason to doubt it at this time. We do recommend you have arc fault detection on by default for safety and code compliance.
Normally the standard procedure is if you are getting an arc fault, make sure you manually clear it, and if it happens again its time to start checking termination points, J-Boxes, MC-4 connectors and wires. You can isolate strings by taking them all off and then adding them back one at a time each day and seeing which string gives you an Arc Fault on the Sol-Ark.
I am not in the finger-pointing game by any means but if you are having TIGO events several timesa day, its possible that when the RSD is shutting the PV power down it can at times resemble the pattern our ARC Fault detection is looking for. Just a guess.
Side note: If this is a 15K inverter please be sure you are using two RSD transmitter cores on your PV wires so that the PLC signal from the transmitter is stronger and better able to reach the RSD modules on your PV panels. The 15K is known to emit its own high-frequency noise that can interfere with this PLC signal, but in all cases having 2 cores fixes the issue. Best rule of thumb is every inverter should get its own transmitter and two cores for its PV strings. It is not necessarily required as many installs don't follow this rule, but it's pretty much guaranteed to prevent the issue explained above.