In the Changelog it says that this bug has been fixed but it is still appearing on my iPhone
MCPE-48322
MCPE 1.12 Crashes whilst logging into Xbox Live while being offline
Resolved
Duplicate
1
Milch karl
(Unassigned)
Unconfirmed
iOS
iOS 12.3
1.12.0
Retrieved
Thank you for your report!
We're actually already tracking this issue at MCPE-33316, so we will resolve and link this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.