There was a bug reported in the Show Manager. It looks like the same bug is in the Sequence Editor on the Functions tab. I've reported this on the Show Manager forum topic here.
viewtopic.php?f=22&t=12278
4.12.4
Windows 10 x64
The fader values of a Sequence step, can be set to zero, depending on the sequence of your clicks.
Click the Sequence you want to edit
Click the step you want to edit
Switch between tab view and all channels view
Click the All fixtures tab
ALL FADER VALUES ARE SET TO ZERO
This only affects the first step you click on. All other steps are set properly.
Click the Sequence you want to edit
Switch between tab view and all channels view
Click the All fixtures tab
ALL FADER VALUES ARE SET TO ZERO
Click the step you want to edit
All values are set properly
Click the Sequence you want to edit
Switch between tab view and all channels view
Click the step you want to edit
Click the All fixtures tab
All values are set properly
If you use the 2nd or 3rd method, when you go into your Show, all values are set properly.
I hope this helps.