We have consistent problems with customers not being able to purchase products after we update our inventory and mark products as visible. For many customers, the products remain listed as "Unavailable" even though we've changed them to "Visible" and there is inventory to purchase. I believe this is a problem with a local cookie in users' browsers that is somehow not getting killed or updated properly. We've also tried republishing the site after changing product status and inventory, but this does not seem to solve the issue. We're at a loss as to how to resolve this.
Thanks for the further insights and willingness to look into this! I have done some testing and sent some screenshots through my email thread with Square Support, but would be happy to share those results here as well.
I made two items visible for testing purposes:
Square Community
Square Products