Quote Originally Posted by ocelot27 View Post
[...] I doubt the tape had anything to do with it [...]
And I think that the tape might just have done it in the end. Sometimes an angle change of 0.8 degrees may just make the difference between an angle just too low for a decent bevel to be formed and one that results in stable edge. Another reason might be that you possibly created a secondary bevel, which held better than the one set without tape. Maybe they're two parts of the same reason.

Or maybe it was something else, but this is my best guess.