JBL Tune 510BT stuck showing “Connected” but not actually connecting

I’ve been having an issue with my JBL Tune 510BT. It was working fine before and connected normally to my phone and laptop, although it occasionally had some connection issues.Recently, it stopped connecting properly to either device. I removed/forgot the headphones from all previously paired devices and turned Bluetooth off on all nearby devices, but the problem still persists.

The strange part is that when I turn the headphones on, they immediately play the “Connected” sound, even though Bluetooth is turned off on every nearby device and nothing is actually connected.
I also tried the factory reset by holding the + and − volume buttons simultaneously for more than 5 seconds until the white LED flashed. However, after turning the headphones back on, they still immediately say “Connected.”

Did anyone have a similar issue and were you able to solve it?