Great question — answering as the UphillTech team:
Yep, filler up with a finger swipe of caulk & see if it ever reappears. It's likely just a paint separation from temperature & humidity effects on different materials.
Full answer by Iggy: https://diy.stackexchange.com/a/81176 (CC BY-SA 3.0).
Need it done for your business? UphillTech.
