Duplicates due to timezone
I have an internal transfer that is set to happen on the 12th of each month. My guess is that it happens at midnight (Paris time).
I have two fetch: one around 00:35 (Paris time) and then another one between 2 and 4 AM.
As we can see on the screenshot below the first fetch (23:30 UTC) thinks it was done on the 11th (my bank does not provide the hour, only the date), resulting in a duplicate: