Also orthotics cause itI'm not an expert on the matter, but its been discussed (in past versions of this forum) quite a bit. If I'm not mistaken it basically falls into one of 3 reasons:
I have a feeling the OP needs to go up in width for general volume issues, ie I think his foot is pushing out at the instep the base of the heel cup.
- Defect in manufacturing, (it seems there was a brief period of time some years ago when this was prevalent, but has since subsided).
- Improper size.
- Last does not work with that foot.