Tis a mystery, particularly without seeing your command or your history window to know what it's doing. This test command is working for me, but I haven't tried it with a live call.
<?xml version="1.0" encoding="utf-16"?>
<!--VoxCommando 1.9.2.1-->
<command id="1145" name="Escape GV" enabled="true" alwaysOn="False" confirm="False" requiredConfidence="0" loop="False" loopDelay="0" loopMax="0" description="">
<action>
<cmdType>Launch.RawParam</cmdType>
<params>
<param>C:\Program Files (x86)\Mozilla Firefox\firefox.exe</param>
<param>https://mail.google.com/mail/?voice&pli=1#inbox</param>
</params>
<cmdRepeat>1</cmdRepeat>
</action>
<action>
<cmdType>VC.Pause</cmdType>
<params>
<param>7000</param>
</params>
<cmdRepeat>1</cmdRepeat>
</action>
<action>
<cmdType>InputKeys.Send</cmdType>
<params>
<param>{ESCAPE}</param>
</params>
<cmdRepeat>1</cmdRepeat>
</action>
<phrase>do the thing with Google Voice</phrase>
</command>