I've found a what appears to be a bug in the version 1.6 :
On any group of fixtures I create a first step with dimmer relative at 0 and width at 25 (or whatever, look like the problem is here), second step with dimmer relative at 100.
Then I set a MAtricks on just 2 XWings, I then apply a phaser of '0 thru 360 thru 0' on my steps.
When I store this fx as a preset everything is working fine when I call it. But when I store this (from the preset or directly from the programmer) as a cue in a sequence, the sequence play for a short time and then stop.
You can easily replicate this on a blank show and see by yourself.