Hello zotsf,
Are you only experiencing this issue when pausing videos in YouTube, or does a similar thing happen when pausing/stopping videos in other video services or apps as well? Does changing the browser that's being used at the time seem to help? These can help to get things isolated down.
You may also try testing things in an newly created Admin account on the Mac, as this helps to see if it's a system-wide issue or specific to the current user account.
This page can help set up the new user, if needed: Set up users, guests, and groups on Mac
Add a user
1. On your Mac, choose Apple menu
> System Preferences, then click Users & Groups
.
If the lock at the bottom left is locked
, click it to unlock the preference pane.
2. Click the Add button
below the list of users.
3. Click the New Account pop-up menu, then choose a type of user.
•Administrator: An administrator can add and manage other users, install apps, and change settings. The new user you create when you first set up your Mac is an administrator. Your Mac can have multiple administrators. You can create new ones, and convert standard users to administrators. Don’t set up automatic login for an administrator. If you do, someone could simply restart your Mac and gain access with administrator privileges. To keep your Mac secure, don’t share administrator names and passwords.
For more information about the options for each type of user, click the Help button in the lower-left corner of the dialog.
4. Enter a full name for the new user. An account name is generated automatically. To use a different account name, enter it now—you can’t change it later.
5. Enter a password for the user, then enter it again to verify. Enter a password hint to help the user remember their password.
6. Click Create User.
Similarly it can also help to test things with a different Bluetooth speaker, if possible, to help determine which component may be causing the issue.
Cheers.