The Calendar Widget in NothingOS 2.6 does not reflect the date change. It keeps showing the date on which the widget was added to the screen. Removing and adding it again to the home screen solves the problem.
If this is not the right place to post these kind of problems, then please do let me know where and how to give such feedback to the team.
Attached screenshot taken on 3rd of August, as seen the date is still 2nd August in the widget