CSS works on one site but not on the other

Hi,
I’m working on identical sites, one for English readers and the other for Japanese readers.
On the Contact Us page of both sites I have placed a button that references a special CSS class. The CSS works as expected on the English page but not on the Japanese page. (Please see image. As you can see, on the Jp page the button text is in blue, it should be white). I’ve checked and the CSS definition is the same in both the En and Jp sites.

The page URLs are:
http://tmpen.ntrand.com/about-us/contact-us/
http://tmpjp.ntrand.com/about-us/contact-us/

I’m not sure if this is related to an inconsistency issue that I have with VC installations: https://hb-themes.com/forum/all/topic/inconsistency-in-high-endvc-installations/

Could you help?

Thanks,

Fara