Hello Andy Ladwig,
Welcome to Microsoft Community.
I noticed that when you stated this issue, you said you could use the touch media controls on Surface Headphones 2 normally on Spotify, so you might want to check if this issue works on other software as well. This is to determine if the problem is occurring in the specific software.
The Pandora App is not a Microsoft product, and if this issue is unique to that App, you may want to contact their customer support and ask if the issue is a compatibility glitch, or if there are options in Pandora to set and adjust your Bluetooth headset device:
https://help.pandora.com/s/contactsupport?language=en_US****
Disclaimer: This is a non-Microsoft website. The page appears to be providing accurate and safe information. Watch out for ads on the site that may advertise products frequently classified as PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.
Microsoft provides no assurances and/or warranties, implied or otherwise, and is not responsible for the information you receive from the third-party linked sites or any support related to technology.
Best Regards,
Mitchell | Microsoft Community Support Specialist