Phones receive updates monthly and apps often daily. So while your habits haven't changed, the phone's software certain has changed.
"What services/tasks are included in data overage?". That information is on your phone. The only accurate record of your data use in on the phone itself. It's private.
If your phone says you used more data than you allotment, then it did. You can scale back on use of which ever apps are causing the overage.
See your data use on the phone ....settings. Data usage. Scroll down to see apps.
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