When working with some spreadsheets, I get these very random lines that are just in the middle of the sheet. When you click on them you can resize them to a square. I have no idea why they're there (not put in by me or anyone else who uses the spreadsheet) and it's really distracting. If you delete one you'll find several more underneath.
Has anyone come across this before?
I'm using the latest version of Office 365 and have attached a photo of what I mean.