When you bind HR92's to a zone you must always bind every HR92 in the zone in the same binding process.
If you bind one HR92 and complete the binding process then go back and bind a second HR92 the first will be removed!
You bind the first HR92 as the one you want to be the temperature sensor for the zone and then when asked if you have further actuators to bind to the zone you bind the remaining HR92's for the zone.
Letting us know what the problem was instead of deleting your post will be helpful to other people who may have the same problem as you in the future.