Factorio Forums

I was extending long belt by moving it one space higher, removing no longer needed support platform along the way. Then I added missing part to fill the gap and it worked fine, but notification stay even after reloading game.
So everything is here and all tiles are in place, but notification doesn't go away. I can attach save file if necessary.

I suggest posting your save for this issue.
Also, have you tried building platform tiles around the alert? That makes them go away for me.

I'll assume you pinned the alert, if not, see above...

Building around fixes the issue, but removing such temporary tiles causes it to appear again.
I used "remove platform" blueprint and it fixed the issue without actually removing anything.

Save file