Both times I found the dreaded purple line, it was after returning from trips to places I probably won't be again for awhile.
I fixed the issue on the photos I wanted to print by going into Photoshop and using the healing brush set to just about the width of the line and holding down the shift key to keep it straight and then saving it back to Lightroom. I have an old version of lightroom but it didn't have any tools that worked as well as Photoshop, maybe it does now.
Somewhat tedious but I only did it for selects that I was going to do something else with like print or export to instagram etc. One in awhile I come across a photo from these two time periods that I want to use and i go and perform this action again.