When a Unison CME/CMEd/CME is reset, the current DMX512 output levels are stored in the output buffer. When the processor reboots, these levels will return, but the preset will not be playing. Levels below 100 can then be changed by playing presets, manipulating zones, or by an external DMX512 source.
However, any zones which have a DMX Input Mode of Pile-On that are at 100 can only be turned off by a Unison Preset or by running "All Zones Off" or "Local Zones Off" in the CME/CMEd/CMEi Diagnostics menu (DMX512 input will not affect them). This is because Pile-On is a "greater than" relationship, not "greater than or equal to".