Recently, when editing events (only when editing- not when adding new), under the tickets section, two price slots will appear. Not ‘price’ and ‘ sale price’ but ‘price’ and ‘price’ and *then* sale price. You have to fill both price fields in with the price or else it displays as free.
This was reported to me by a client. Attached is a screenshot she sent me. All software and add-ons are up to date.