Woocommerce cart and checkout pages are dowloaded as html

Hi! I came across such issue – when I turned on Page caching, Cart and Checkout Woocommerce pages didn’t updated after adding new product to cart.
A added these pages to “Never cache the following pages” as “cart\.html” and
“checkout\.html”.
And once I noticed that when I click on cart link, the page is just downloaded by Chrome as cart.html file…
Could you, please, give any suggestions what could be the reason and what can I do?