PFrames component aligning middle frame different

Hey guys, I've got a problem using the Perpendicular Frames component on a curve in my model. I've extracted the curve from a Brep using the Brep Deconstruct component and then List Item to get the cuve I want to use.

I want to then divide the curve and paste in a few other components (diamonds in my case) that are placed perpendicular to the curve. To achieve this I'm using the Perpendicular Frames component to extract frames from the curve and then I orient the other geometry to these frames. This works fine, except for one issue I have which is that the middle frame generated by the PFrames component seems to be rotated 90 degrees from the other frames. Because of this the geometry I try to orient obviously also orients in the wrong direction. 

Attached are two images that hopefully illustrate the problem, you can see that the middle frame has another direction in comparison with the rest. Why is this happening? It must have something to do with the initial curve and at one point I thought it might be because I used 'join curves' to create the curve from two other curves but when I tried it on another curve that I also extracted using Deconstruct Brep that wasn't joined, the same thing is happening. Does anyone maybe know what's happening here? Thanks!