One of the first effects a lot of us did when Motion 5 first came out were masks using OSCs (on-screen controls). It was new and cool.
That was Motion 5.0.0. When Motion 5.0.2 came out -- a whole lotta those effects BROKE. The bug isn't in FCPX --- ***I promise*** --- the bug was in Motion (and actually kind of still is... but it's very arguable if it is a bug and not just a kind of "gotcha" -- easily taken care of.)
Not everybody experiences the bug in FCPX. Part of the reason why that particular effect is still available.
Anyway, I redid the 7 pt Mask, but changed the name:
http://sight-creations.com/free_stuff/BSpline_Mask_7pt.zip
I also have a 10-point Mask:
http://sight-creations.com/free_stuff/10_Point_Mask.zip
[Both of these masks work in SD... just checked]
Others have masks too (Alex 4D has an 8 point and I'm sure there are many others).
It helps out if you find an effect that doesn't work if you would go back and leave a comment on the video page on youtube. I've fixed several of the early Motion templates that use OSCs. I'll fix them if they're reported broken.