Someone has to kick in the open door, so let that be me...

Your razor might be sharp enough for WTG & XTG, but just not keen enough for ATG, certainly if your beard is coarse.
You could try stropping again, before your ATG pass. You could perform a HHT. I'm not saying that a razor that fails the HHT can't go ATG, but since I make sure my razors pass that test I never had any problems anymore with pulling or skating.

I would also like to suggest that you skip the XTG pass and go ATG immediately after your WTG pass. Once you master ATG, you can add the XTG pass again and see what that does for you. I always perform my ATG on a layer of "lathery water", just to make the razor glide over my skin, but translucent enough to see really well what 's exactly going on. It's visualy quite rewarding to see your face becoming more BBS with every gentle little ATG stroke you perform.

Best of luck,

Bart.