After upgrade to IOSiOS 13 from 12.4, I noticed that personal hotspot isn't working anymore over WiFiWi-Fi (via USB is ok).
Tested on two computers with Win7. The PC can connect to WiFiWi-Fi, but no valid IP (IPv4) is assigned and no connection is working to internet.
EDIT
Seems that IOS 13.1.2 Personal Hotspot's DHCP is not working, at least on Win7. What I did is I assigned client IP manually (my PC)
IP Address: 172.20.10.11
Subnet Mask: 255.255.0.0
Router: 172.20.10.1
DNS: 172.20.10.1
Now is working....
I wonder why I paid > 1000 eur for it including Watch and still have trivial bugs introduced with new updates.
They didn't make regression tests? Totally disappointed!