The "Filament 3 Error" - Successful loads turn into unload and MMU Load Failure  

The "Filament 3 Error" - Successful loads turn into unload and MMU Load Failure

Hello everyone! As a background, I own and operate 7 MK3's, with 3 of them having MMU's installed with a 4th on the way.  They all run around the clock and therefore have accumulated 10's of thousands of hours amongst them.  I've dealt with many issues, but there's one that I haven't seemed to be able to resolve: The Filament 3 Error.

"Filament 3 Error" isn't something that shows up on my screen or anywhere else for that matter.  But for some reason, all three of my printers have experienced this issue over time, but ONLY when switching to Filament 3.  Here's how it goes:

1. Printer is doing fine on filament 1, 2, 4, or 5.
2. Gcode calls for a swap to filament 3.  Unload goes perfectly.
3. Selector moves to Filament 3 without issue
4. Filament 3 begins loading
5. Filament 3 is successfully sensed by the MMU FINDA, and is then sent down the Bowden quickly.  The hot end FINDA successfully senses Filament 3 and stops the rapid descent of the MMU.  Then the magic happens...
6. The printer acts as though it is going to print with Filament three, but never begins the wipe on the tower.it
7. The MMU retracts the filament.
8. The above cycle will repeat steps 4-7 four to five times before it gives up, the print is paused, and then the hot end retreats to the left and the bed comes forward.

Has anyone else experienced this?  Everything is going correctly MECHANICALLY multiple times consecutively which is a feat in and of itself.  But there's clearly something wrong in the gcode or the printer software causing this to happen.  All three printers have had this happen from time to time, so I'm beginning to think it's the slicer or gcode causing the failures to happen.

Temporary fixes (~50% success rate at recovering prints, different tactics work for different prints)

1. Reset button on MMU and resume print.  This sometimes is all it needs.
2. If 1 fails, pause print, reset button on MMU, load filament 3 to nozzle, resume print.  This will often work, but it will cause for the MMU to throw the "light up like a Christmas tree crash error" when it goes to unload filament 3.  So it's manually pull out Filament 3, then reset MMU, resume print.
3. If 1 and 2 fail, then you convince it to feed the filament to the hot end while manually forcing the filament into the nozzle by pushing the filament on the spool side of the MMU.  This SOMETIMES works, and is a last ditch effort before the printer gets flipped off and the wasted parts get hurled across the room.

TL;DR - filament 3 frequently goes through a cycle of successful loads without ever restarting the print, then throws an error and pauses prints.

Any tips or guidance is welcome!  Printer and MMU running most recent firmware iterations.