Hot spot won't autoconnect

My iPad used to seamless automatically connect to my iPhone when the hot spot was activated. Then it started only sporadically auto connecting. Recently it will not auto connect. I have to go into Settings and select the hot spot. Every time. The only correlation here is the "upgraded" iOS versions Apple rolls out. I would like to get the auto connect feature restored. Any ideas? BTW I have recently to do hard resets on both devices and set up as new, so solve other persistent operational problems. So it is unlikely there was some corruption lurking.