Does your version of Deep Freeze have an Advanced Configuration tab and a setting for "Allow User to Change Time" ?
https://www.deepfreeze.com/webhelp/DFWC/DFWC_EN/index.html#page/EN/Chapter_EN.1.111.html

From the link:
"Allow user to change the clock – Select this option to allow Frozen users to adjust the system clock. Enable this feature during Daylight Savings to allow Windows to update the time automatically each season."