In WooCommerce, I can't chage Product Permalink setting(404 error)…

Hello!

I’m using WooCommerce version 2.5.5.
After the update to the latest version(2.5.5),the permalink setting doesn’t work. (Before update with 2.5.2, it worked.)

I want use “Shop base with category” setting in Product Permalinks.
But the product single page is not shown with this setting(404 error).

And I found that after this setting, the setting text of “Permalink Settings for Custom Post Types” looks like wrong.
There are double slash like “//” in the product permalink structure like this.

product
https://localhost:8888/mystore//store/%product_cat%/%postname%/

If someone knows about how to use this setting correctly, please help me…

Thank you in advance.