Can't submit forms if mobile data is set to 'Restrict Background Data'

1. What is the problem? Be very detailed.
Restrict Background Data stops submission of forms to Googlesheets via 3G/4G - I just get a blank screen and nothing happens, no messages or errors, just appears to 'hang'.

2. What app or server are you using and on what device and operating system? Include version numbers.
Android 4.4; ODK Collect 1.22.4

3. What you have you tried to fix the problem?
Turn off Restrict Background Data temporarily!

When this function is disabled, the forms send without any problem, so I assume that there is some form of background authentication?

This is really just to highlight an issue I discovered - it is beyond ODK I think, but it is maybe useful for folk to be aware. Perhaps I'm the only person that still has this function set to save on my data allowance and battery, and still using an older phone...