It sounds like your JBL Charge 3 might be experiencing interference or an internal issue. Here are a few things to try:
# ***Reset the Speaker:*** Hold down the power button and volume up button simultaneously for about 10 seconds until the JBL logo blinks.
# ***Update Firmware:*** Check if there’s a firmware update available via the JBL Connect app.
# ***Check for Interference:*** Ensure there are no nearby devices causing interference.
If these steps don’t resolve the issue, the speaker might be defective. Consider contacting JBL support for further assistance or a possible replacement.