I'm not sure why PB2 worked, but PB3 has trouble with this due to a combination of the small scale of the model and also the type of path. There seems to be an issue with PB3 when extruding along a circular path where the path's axis is horizontal. The issue will not always occur. It depends on a number of things so this is somewhat of a corner-case that you have discovered.
We have logged this issue and will try to fix it in a future update. Thank you for bringing it to our attention.
As a workaround, avoid using very small profiles and try not to extrude around a circular path that has a horizontal axis. It will more likely work if you extrude along a circular path where the axis of the circle points vertical. Then, after creating the Profile Member, rotate it and move it into the proper position.