Cannot go to Customize when Polylang is on


as the title says - I do not have an access to the customize theme section, when the Polylang plugin is on. Before it was working, I guess the problem appeared after some polylang or jupiter update, but I just saw it today.
When I try to get to the customize, I get an e-mail from wordpress, that it detected a technical problem in the “Jupiter X Core” plugin.

Does anyone has the same problem?
Is there something I can do?