Its a problem with the app's coding for the Roku platform.
The same app on different platforms are very different "under the hood" - though they may look very similar or even identical in the UI, underneath the code is very different.
RokuOS is very different from tvOS or Android OS or webOS or Tizen OS etc (all are streaming platforms, etc), especially in terms of how apps are coded and interact with the OS.
I recommend a multiplatform streaming strategy for the very reason this thread exists - bad software (firmware/middleware/app) updates can/do happen at any moment, and if you want uninterrupted streaming, you'll need access to a different platform.
Aside from that, there are functionality differences between apps/services on the different platforms, so if you want the best/preferred app experience, you'll need multiple devices from multiple platforms.
I recommend 3 different platforms, one of which is Android/Android TV based for the purpose of sideloading apps.