Hi @Anonymous User , how are you?
Could be a GPS problem or a bad software implementation, effectivily the watch can count the amount of floors climbed but not when you are sleeping or without movement.
Let a Samsung moderator talk to you, they will give you a solution to check, send data to Samsung or try to fix the issue if it's possible without warranty or without to use tecnical service extreme.
Sometimes GPS change to a other ficticial coordenates because other people's problems or 3rd Parties.
Check replies next week and speak with them 
Hi TonyG1, I only wish that you can fix your problem.
Often I can experimentate with other GPS sources and programs that sometimes get a not real GPS possition for some different reason to the App or Watch. When it get GPS coordenates, it get height values too, then could be possible that Smart Watch can show false values sometimes and to make bad calcules itself. Depend if you lost the GPS signal,a bad read or something similar. Only I can tell you about my experience and only a one month of Galaxy Watch.
Please, let to a Samsung Tecnical to check, they will try to help you, be patient, you wrote two days ago in a weekend, let a little bit time, they will be bussy in others task, but I'm sure they will answer you as soon as possible. Also you have the Technical Service available, usualy free, for the customers always that they can use it with warranty and it be a correct incidence.
Thank in advance and have you a good day 
