we are not aware of issues with Redmi Note 4 etc in general - neither can I find anything related in the Play Store Console of either TMM or the Catalyst Service.
So I don't believe/ hope its a generic issue.
Could you please double check the permissions of the application you develop. The app needs access to the external SD Card - as the subscription gets read from there. Sometimes the switch in 'Settings' --> 'Apps' --> 'Permissions' is off although the manifest is correct and the runtime intent was sent.
Plus - as the application is not registered so far - you need to test based on debug builds. Release builds will trigger an application finger print - which will fail currently.
Another thing that might shed some light here are the logs collected by TMM. So if you open the Developer Gateway of TMM (details in the TMM dev docu) and enable logs as described there, then MINIMIZE TMM (so please don't kill it), ensure you are disconnected from Catalyst and try your app.
After doing this 2 or 3 times there might be issues collected in the log.
Keep in mind that TMM should not be connected to Catalyst during any testes as Catalyst is a 1:1 connection - so application to soft GNSS receiver.
The devices that cause the problem are also not rooted or anything similar, or?