Hi Felipe,
Are you able to attach your XLSForm so that I can troubleshoot further? Do you have 'GPS2' selected for your 'reciever_id' question and 'no' selected for your 'running_check' question? From your screenshots it looks like your 'Antenna Offset Check' and 'Result' calculations depend on these selections. Is there a reason you have 'relevant' expressions set on your 'calculate' questions?
Brett