Thanks for replying, Kampsen761, and that additional info, it really helps! To help isolate this, please make sure you have the latest version of the apps you are having this issue with: How to manually update apps on your Apple device - Apple Support
Next, go on your iPhone to Settings > General > Background App Refresh and make sure this is turned on and is enabled for the apps having this issue, and also make sure you don't force close the apps having this issue, as that could explain not getting notifications for these apps: Switch apps on your iPhone, iPad, or iPod touch - Apple Support
Another simple step to try is just restarting your iPhone: Restart your iPhone - Apple Support
If you are still having this issue, please report it to the app developer so they can fix this in their apps in future app updates: Contact a third-party vendor - Apple Support
Have a great day and thanks for using the Apple Support Communities!