This is an interesting one. If it was the Roku device, it would seem it would impact all the apps. It doesn't, as you said.
That points to the apps. However, if it was the apps, it would happen on other Roku devices. That is, my Roku device would have the same problem your Roku device has, if the apps were the same, and were the issue.
Now, just to correct one thing you'd indicated: you're treating the apps for the various devices as being the same. They aren't. They all run on different operating systems. You can't run an Apple app on an Android box. That means the app code is different for the apps on those platforms. And different code is a different app, regardless of its name and company that created it. So, if a Roku app works one way, and an Apple app works a different way, it's not because of Apple or Roku, it's because the apps are different.
That doesn't solve things, but it does give a better understanding of the landscape.
So, which Roku device do you have? There is no "Roku+" device. Is it a Roku Express+, a Roku Express 4K+, a Roku Streaming Stick+, a Roku Streaming Stick 4K+? I think I'm missing one or two. Anyway, go to Settings > System > About and provide the model number. Also give the software version/build. Maybe that will help run down what's going on.
DBDukes Roku Community Streaming Expert Note: I am not a Roku employee.
If this post solves your problem please help others find this answer and click "Accept as Solution."
Try removing the channel(s) from the Roku home screen by navigating to the channel tile, pressing the * key on your remote and choosing 'Remove channel'. Then restart your device from Settings>System>System restart. Once your player starts up again, add the channel(s) back once more.
Does this clear up the issue you are seeing? Please keep us posted what you find out.