Hello,
I see some problems in your last printscreens:
1. Do not set all options (min + max vs fix). Just set only fix limit to 1 without using min and max limit.
2. All your reservation types have same name so you can not be sure what are you selecting.
3. Your bookable item in printscreen1 looks different than bookable item in printscreen2. Reservation types have different names.
I am not sure, what is your problem at the moment. Maybe some problems are caused by settings of min + max + fix. It is possible. Try to modify it and we will see.