Hello WuB WuB.
Thank you for using Apple Support Communities. It sounds like you're experiencing issues with a specific third-party app. You mentioned that you've noticed that opening this app also enable Location Services. If so, we'd like to assist and also point you in the right direction for help.
If you noticed that this specific app is using Location Services, you can disable it by following the steps listed within the resource below:
Turn Location Services and GPS on or off on your iPhone, iPad, or iPod touch - Apple Support
If this doesn't help, you might want to delete and reinstall the app if it's not properly working. If you're not familiar on how to perform these tasks, check out the resources below:
Delete apps on your iPhone, iPad, and iPod touch - Apple Support
Redownload apps and games from Apple - Apple Support
Lastly, if reinstalling the app, and confirming that you've disabled Location Services access to that specific app doesn't help you, reach out to the app developers for that specific app. The link below can show you how to reach them:
How to contact an app developer - Apple Support
We hope this information is useful. Cheers.