Scheduled rules execute a hour after they are supposed to
Cause 1:

After a rule is scheduled (using the Rules Scheduler submodule), it will only actually execute next time cron runs. Example:


schedule a rule to execute at timestamp X.
if the next time that cron runs is at Y mins after timestamp X, then the Rules execution will only happen then (= at Y mins after timestamp X).


Cause 2:

If your site is set to the correct timezone, but your users are set to a timezone that is 1 hour ahead, then that might also explain what's happening. In that case, correct the timezone accordingly.