Print stops

I recently updated to the lattest firmware on the X1c.
Now when I print it stops extruding at different layers. often around layer 10- 15. It continues moving as if it was extruding but. no filament is coming out. (no spageti)
Tried replacing the .4mm nozzel. no affect.
Tried different types and brands of filament. No affect.
Tried different slots in the AMS. No affect.
Tried replacing the ptfe tube. No affect.
happened to clean the lead screws and rods. Not expecting any change from rod cleaning.
Had the same problem with different models. No affect.

what else can I do to fix. I suspect it has something to do with the firmware update. How do I downgrade the firmware?

By firmware I mean the software downloaded to the printer.

You can most easily downgrade from the Handy app.

Let us know if that fixes it.