IPF 780 (OSX) Suddenly prints 3+ ~6 foot pages after initial print with Job: GL2 004, GL2 005...

[Y-na-T]

My IPF 780 is suddenly printing several 6 foot blank pages after the initial print job (which prints without issue.)

Printing from both Lightroom and Preview on OSX Sierra.

I've gotten good at catching this and canceling print job / immediate power down. I have yet to see how many pages it attempts to print beyond 3. If I'm late to the cancel (within ~10 seconds), it will roll out 6 feet and cut the paper.

The print job name is "GL2 00X" where X is the print number.
User Name: (this is blank - my prints usually show my name)
Page count: 0
Interface: USB
Size: 1936 sq. in.​

Does anybody have any ideas about what is going on here?

I am hoping the oddness with blank user name, print job name "GL2" might mean something to somebody out there.

Thank you!