Issue Summary

This is reproducible on Data Center: yes

Steps to Reproduce

1. Create a fresh Confluence 8.0.0 instance
2. Create a Space
3. Create a Page
4. Set browser time zone to America/New_York (UTC-5) 
5. Insert date using date picker
   1. Type // while editing a Confluence page
6. Click any date on the date picker

Expected Results

The date on the Confluence page reflects the date you clicked.

Actual Results

The date reflected on the Confluence page is one day prior to the date you clicked. 

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available