Thank you for the report Chuck Kosta.
I have tried to recreate the bug using the demo data and the out-of-the-box application; here are the steps I have followed:
1) setup an instance of OFBiz 14.12 with demo data (./ant clean-all load-demo start)
2) go to Catalog->Promos->select the first promotion and then select the "stores" tab; here is a shortcut (authenticate as admin/ofbiz):
3) in the screen, the input box with column named "THROUGH DATE" is rendered using the @htmlTemplate.renderDateTimeField macro (see the file EditProductPromoStores.ftl)
4) select a date value and submit the form; the data is saved in the database
I have tested it with Chrome.
Could you please confirm if you can run the same steps? You could compare the fields set in this macro cal with the ones that you set in your screen and hopefully this will provide some clues about the nature of the issue.