Hi Marko,
Just tried that – I disabled one by one settings and tested, nothing helped.
During the tests I received an email from WP saying that “Facebook for WooCommerce” plugin causes a fatal error on my side with the link of product change page.
I disabled Facebook for WooCommerce plugin and product change works with W3TC enabled.
Seems there is a compatibility issue between W3TC and Facebook for WooCommerce plugins. I have to disable one of the plugins to be able to modify a product.
Semyon