podarok

There have been a lot of firmware updates for a while. It's a bit of a different beast than the other models, with the dual conversion.
No. There is space for only one firmware. If you need 71.93, it's available as well. But if your clone (if it indeed is a clone) won't load or run stock 71.97, then it probably won't load back 71.93 either.
Your machine looks fairly legitimate; the only thing is the "Xpert" in the name. Maybe they didn't want to use the correct word ("Axpert") for some reason, or maybe it's a sign of a clone, I don't know.
Is there a small date sticker further up the unit, with "2020" on its side, 12 squares with the numbers 1-12, and with number 10 blacked out? A bit like the below, but with 10 blacked out instead of 1:

If so, your machine seems to be legitimate, and you should have no problem loading 71.97. Though you may want or need to update the removable display firmware as well.
If you are concerned about the large gap in firmware version numbers, 71.94 is also available in the files section.

I wish I'd realised that it's a King. Axpert King main firmware version 71.94 (one minor revision after yours) fixes some sort of PV dropping to zero problem. So that sounds quite relevant to you.
The latest two Axpert King firmwares (main unit and removable firmware) are presently the first two files in the files section of this forum: https://powerforum.co.za/files/category/1-files/  Of course, if yours really is a clone (as opposed to a legitimate but re-branded), then who knows if the updated firmware will work. But it looks promising, from what little I've seen.

Certainly sounds like a dip and freeze. Two simple ways to reset SCC are to:
disconnect solar panels from the inverter until the solar panel icon stops flashing then reconnect them. change mode to ecomode until the batteries are fully charged and the pv restarts . You do have to allow AC charging for this. Once the SCC restarts you can change mode back to automatic then sbu. Option 1 is much faster but you need to be at the inverter. I use option 2 if I need to remotely reset the solar.

Just to provide some closure to this topic....
We tried a full rewiring of the parallel and load sharing cables. We changed some parallel boards. We flashed updated firmware.... all to no avail.
The issue was resolved after reading about another installer of a Victron system who accidentally coupled the AC output to the circuit to the AC input circuit. When the AC grid returned the 2 waveforms were naturally out of sync and the Victron made some unpalatable noises for about 20 seconds before shutting off with the overload light "ON". One of the observations that this person made was that the Victron's reported frequency fell to around 40hz! This would make sense.
It led us to wonder whether there was not a possibility that somewhere in the inherited installation there wasn't a direct connection between the AC input and the AC output. We eventually found this in the rotary changeover switch at the main supply DB! The terminals on this rotary switch are very close together and a single strand of the 16mm^2 incoming live cable was touching another terminal which bridged it to the output live only when the changeover was switched! A new changeover switch with better spaced terminals was installed - job done! Everything is now operating exactly as it should!
School fees!
The upshot however is that all the inverters have been reflashed with the latest 73.00e LF1 firmware (Which is fantastic!) and the system has been checked with a fine tooth comb!
Thank you to everyone who provided input.

Yup, the inverter will slow down its own frequency to sync with the grid frequency, If you put it in  situation where this can't be achieved, it will end up at some extreme value.