I am new here with HE so am just learning and more than likely mucked up my rule.
The rule is to run a bathroom fan with the humidity gets 15% higher than elsewhere in the house. This all works properly. I only want the rule to work while HE is in Day or Evening Mode.
The Manage Conditions section is simply a repository for your conditions. They won't have an affect on the rule unless you include them in an Action. For example, you include the mode in a conditional action like IF (Mode in Day) THEN...
You also made the Delay cancelable but you don't have an action to cancel it (i.e. Cancel Delayed Actions). This won't cause an error but might result in undesired results. The rule will trigger every time the bathroom humidity report +15 at or over the kitchen humidity. Here's a scenario to consider.
9:00 bathroom humidity reports +15 over kitchen and turns on fan, delay scheduled to end at 9:05.
9:03 bathroom humidity reports +17 oven kitchen, fan is already on, delay scheduled to end at 9:08.
9:05 1st delay over, fan turned off.
9:08 2nd delay over, fan already off.
The fan didn't run the full 5 minutes after the +17 report because the first delay turned it off. I don't know your system but the inclusion of the cancelable on the delay indicates to me that you may want to keep the fan running if another trigger event happens within your delay window. You could also consider using a Wait action for the humidity drop below a certain value, say +10, before turning the fan off.