How are you engaging the Freeze function? Are you pressing the button in the lower-right corner of the plugin? Setting the Feedback knob to FREEZE on its own won’t guarantee the signal will truly freeze, as some parameters in both plugins can cause the signal to decay; pressing the FREEZE button should set all of those parameters to a setting where they won’t decay.
If your reverbs are decaying even when hitting the FREEZE button, please contact support@eventide.com so we can take a closer look.