I think that will be hard to solve without at least some photos but offhand the only way I would see the pole forming  an S shape is if a shaped pole section was in the wrong order and somehow held in the wrong direction. The trouble with that is that as far as I can tell the HD2+ doesn't have shaped pole sections.

It seems likely that you have the pole sections mixed up.  If it were me I would take the poles apart again and systematically re assemble them without the shock cord using the tent body as a jig to figure out how the poles are supposed to go together.  If they are mostly identical then there should be only a few possible variations.

Not sure if it is useful or not but here is a photo of what I believe is the same pole set you have

https://www.rei.com/product/845457/rei-co-op-half-dome-2-replacement-pole-set

and here is a fairly extensive review of the HD2+ with photos

https://www.trailspace.com/gear/rei/half-dome-2-plus/

From those you might be able to get a good idea as to how the pole sections are supposed to be assembled.