In my exported csv, I noticed that there is some variation in the way that last_purchase_date is formatted. E.g:
This appears to change over time and is not related to me updating the records.
For example, people who registered this month have m/d/yyyy, whereas the previous 3 weeks are formatted dd-mm-yyyy, which Excel won't recognize as a date. Looking at the whole membership list, I see this began in mid-March and has changed periodically since that time. The other date fields do not have this formatting problem.
What is the correct format? Any insights or fixes?