Products unavailable in English setting only

[maota]

Hello,

I just noticed, that some products in my shop show up as unavailable, when I change the language setting to English. The shop itself is in Japanese. In Japanese the products are available to purchase. 

https://naensis.com/collections/all

I have the shop set up as depending on your setting and country, it switches to English (if that matters).

I would appreciate any help in solving this issue!

Thank you.

Edit: I noticed, that once I click on a different color and size, it becomes unavailable. If I refresh the page it becomes available again. Maybe a bug?