Low fluid ?

Going downhill with very low oil-level, could easily do that, as whatever oil is in there sloshes to the front of the pan, leaving the filter sucking air.
Fix your dipstick!
The correct oil level is about at the parting line between the pan and the case. If you pull the dipstick tube out, you can should see the oil at the bottom of the hole..
While the tube is out, you can insert the Dipstick to that parting line, and fix the stick so that it dips there every time.
Cheap fix to save an expensive trans, which may be too late now. IDK.