Hi!
I tried syncing products from Printful, and the images did not upload/sync correctly.
Printful told me that it is the fault of the hosting. Hosting told me to disable all plugins. As I disabled them 1 by 1, discovered that w3 total cache was the one that made that syncing impossible. After I disable it, everything goes fine!
I can replicate this error.
Otherwise, I do like the plugin.
With Best Regards
Voldemārs Baroniņš