Check file, try subselect top and move up with gumball.
Rhino needs to recognize situations that doesn’t work with move face AND report messups like this.
When exploded and points turned on it looks like this:
Why are the extra isoparm moved to 0? Is the calculations happening in a local 0,0,0 that is forgotten to be xformed back to world???
As you can see here, if I make multiple and do it to them all, then all of these share the same location for this messed up isocurve:
Move top face messes up.3dm (75.5 KB)