Some LED signs from the workshop get stuck…i have a sign stuck on my wall that I cant move and my fiance has one stuck in his floor.
If you hold Q (or whatever hotkey opens your inventory) and look up at the top left you should see the “Find Items” button. Click on that and from there you can teleport to the sign or stash it back into your inventory. Hope this helps!
If you let the creator know, sometimes they can re-upload the item tothe workshop. There was an issue after some update where some of the workshop items lost properties and some of them can be fixed, others can’t.