What is this ... black box + line

[MissAppeltaart]

InDesign 17.0.1 - Hello, can someone explain to me what I may have done to cause this? In this spread, there's a black line over the middle of the left page and a black box underneath the right page. The left page shows up in the pages panel, but not in the document itself in preview mode. Both line and box are locked. I tried just about any bug solution I could find (no underlines, no hyperlinks ...). I exported the document to idml and then everything appeared normal but I would still like to understand what I may have done to cause this in the first place. Thanks much!

[Randy Hagan]

Perhaps one of the great lies of the computer age is "What you see is what you get." It's right up there with "I'm from the government and I'm here to help you."

Anomalies occur. If you have the original, flawed document I'd be curious if you could print the missing page. And how it prints. My expectation would be that if you printed it with printer's marks, all you'd see are the crops and registration marks. If you can find it "returns" when you export to IDML and bring it back, I'd suggest that it was always there but your screen was lying to you.

In short, I don't think you did anything to make this anomaly occur. It's just an indication that (to put it somewhat delicately) stuff happens.

Hope this eases your concerns,

Randy

[MissAppeltaart]

Thank you Randy, I think this may well be the correct answer, anomalies occur and stuff happens ...

I was unable to print the flawed pages (there were actual 2 spreads like this I saw later). I was able, though to delete the left hand pages from the spread and insert new blank ones. That made the black boxes on the right hand pages disappear. 

It did not appear in the IDML (there were blank left hand side pages) but formatting on the later pages in the IDML document was all messed up.

Anyways ... I seem to have a clean document again and am crossing fingers. Thank you much!