Since Thursday, all of my ST apps have been triggering in the middle of day (instead of in the evening) apparently at random. Turns out, that they were going off at right time but for GMT.
Went to graph.api to see what timezone my hub was in… it was blank. To resolve, go into app and change the location of your hub a bit and save. You should now see timezone in configuration. Triggers seem to be back on right schedule.