Hi Lucy,
Globus Connect Personal and Globus Connect Server shouldn't be doing anything special with respect to creation and modification dates.
This sounds like a problem with the filesystem or with the host machine running the endpoint.
Do files created without using Globus transfers in the same directories get correct dates?
Your files probably have a creation and modification date of 0 (time 0 is 7:00 PM Dec 31, 1969 EST, and earlier for other US timezones).
This is likely some kind of default behavior, but the underlying cause is going to be specific to the machine where you are running the endpoint.
It's also possible that whatever method you're using to inspect the files is failing and showing you a time of 0.
Some languages (e.g. PHP) do this silently, which can be very confusing.
Best,
-Stephen