Mysterious line on pdf
Erase ALL then deselect everything left drag style...?
It’s probably left over from the BLM’s BOGUS theory of section breakdown -
....sorry couldn’t help myself....
One thing that get rid of phantom lines or objects is to thaw all that you want to keep and wblock it into a clean drawing. You will have to do any paperspace setups and entities in a separate move so for multi sheet sets this is a pain. I had a drawing that wouldn't let go of a deleted line once and this was the only thing that worked.
Using ACAD reminds me of a bunch of villagers sitting around wondering if the rain god is going to do its thing.
Sometimes we just don't question why it does certain things. There is nothing we can do, and we just find work arounds.
I would probably just obliterate the line in the .pdf drawing and try not to say anything bad about ACAD in case it decides to frown on you again.
It’s called a glitch.