Webhook bug?

What does the formula depend on - ie is the record getting edited or is the checkbox changing as a result of lookup or summary fields changing.

Webhooks only fire when the record gets edited not when related records on other tables get edited.

Was that the cause of the problem?

Exactly what you said. My formula was pulling information through a reference from a related table.

So I've been wrecking my brains on how to get around this problem, but I can't come up with the answer.
Here is my formula:
//[Now] - changes to Now() every 30 minutes using table to table sync
//[Store Start Date] and [Store End Date] come from a related table

var date nowDate =ToDate([Now]);

If([Store End Date]>=($nowDate) and 
    [Store Start Date]<=($nowDate) and 
     Abs([Store End Time]-ToTimeOfDay([Now]))<=Hours(1),
       true,false)

What if you use a webhook on the source table, that changes a checkbox on the table in question....