I have a passion and hobby to go through complete literature and review of all iOS and needless to say I haven't missed iOS 12.1.3, 12.1.4 & 12.2 assessment published on various news media and on Apple web page including leading news magazines (Forbes & Fortune Magazines).
No where I could find any link on the problem of "Freezing" faced by you. Introspect and have a complete and thorough check on the way you handle settings on your iPhone.
Read often for a peaceful life.
Solution. See the link below.
If your iPhone, iPad, or iPod touch won't turn on or is frozen - Apple ...
https://support.apple.com/en-in/HT201412