"Preserve Constant Vertex and Feather Count when Editing Masks" not yielding expected/desired result

[DKins]

I have a mask w/ a dozen vertices that I've keyframed across my timeline. After adjusting the vertices I realize I only need the top half of them to do the job. I want to delete the bottom half that are unnecessary, which I have never needed to do before. I knew there was a preference that was related to this, so I checked the option "Preserve Constant Vertex and Feather Count when Editing Masks" and verified that it was UN-checked, since I am intending to change the vertex count. To my surprise when I selected the points I wish to remove, they were only removed until the next keyframe of the mask path. I tried a few different spots along the timeline but observed the same behaviour. I checked the AE reference manual (https://helpx.adobe.com/after-effects/using//animating-shape-paths-masks.html#designate_the_first_ve...) and it included a note that confirmed what I expected to happen.

There are no specific mentions of keyframes so I take the phrase "throughout the duration of the path." to include across keyframes. I checked YouTube but found nothing relevant as a stand-alone topic. I also checked this support forum to see if anybody had discovered a bug that was impacting this functionality. So, is this user error or a bug? Thanks in advance!

[Mylenium]

Since the option was enabled when you created the mask, the info is stored in the keyframes already. This has never really worked any different. The relevant option really just comes into play when creating the mask, but it does not affect existing keyframes. I agreee that it's confusing and may need to be rewritten...

Mylenium