I don't want to answer for @Biotec but here's what I think he is saying. I'm looking forward to his answer based on his experience.I don't have a working lathe right now, but I have a friend & neighbor who's getting one. However, It does have a groove already for the retaining clip. Are you saying that moving the flange will ruin that groove?
I think he is saying that the groove the retaining clip goes into could have been damaged. That could cause the clip to not stay in, and pop out. When you put pressure on the clip in the direction of the curved edge, the clip wants to pop off. I've seen this fixed by the groove being machined to accept a thicker clip or to use two clips (each method assumes there is enough room to do this).