@cjk, so what is the timestamp format in your database? And yes, it’s very good that your system allows you to choose a date or date/time export format.
Getting back to the topic of the post above, data publishers can use GBIF’s “issues” flags to check for date problems, including date format - one such flag is “Recorded date invalid”. For example, in an occurrence dataset harvested yesterday, 7942 records out of 7983 were flagged “Recorded date invalid”. The records I looked at had eventDate entries in the format MM/DD/YY.