They seem to have different issues, hydration being the most frustrating at present.
Menstrual cycle - update it on the watch and looking back the days are now all blank so presumably hasn't synced properly??
Hydration tracking - doesn't update to a new day, you start the next day with the previous day's data, have to go to app, move to 'today' add some water and then sync, and even after that it still shows the previous data target. It briefly also seemed to suffer from the blank was the menstrual stuff suffers from...
Halp?