hmm, good question. I have not seen that issue before.
Care to provide some more details, like which phone you are using?
Have you checked if this issue has already been mentioned somewhere else on the internet?
Firstly, check if you have any manual data limits set in the settings. Maybe that is something that could be limiting the ability to share connection.
There is one nuke-and-pave option that I can think of. But that will reset practically everything that you changed within the settings.
Long press on Settings icon -> App Info -> Storage and cache -> Clear Cache -> Clear Storage -> Delete
And then maybe even Force Stop the Settings app and also restart phone.