FLStudio Envelope Controller Plugin does not update envelope graph if ADSR values are updated tweaking ADSR knobs (as opposed to tweaking ADSR control points on envelope graph directly by dragging them with mouse).
During tweaking after (any) ADSR knob ...
FL Slayer just as example.
Move the selected parameter you wish to link. (in the image knob 'pitch bend 2')
In the Toolbar navigate to menu "Tools > Last Tweaked > Link to Controller".
Make sure "Auto ...