I have been putting up with this VERY odd issue for awhile, and I've finally
come up with a distinction to what may be causing it.

So here's the problem..
In a Document Library, whenever I update a column using a workflow, any Date
values that are previously set are disappearing, blanking out, whatever you want
to call it. They even show in the Versions as being set as blank.

What I've found to be causing this problem is that the DL allows Content Types,
and it only occurs when I choose the date fields to be included in a particular
content type. When the date fields are not in the content type and I update any
fields, it does not blank out.

This makes no sense to me why this would even occur? And after much searching I
have found noone with the same issue.. can someone make sense of this for me
please?