Typeerror: A Is Undefined

in multivendor 4.3.2

not sure what caused this error (possibly some modification) but when I open a category in backend to view/edit (mode='update') as a vendor I get this message on blank page:

TypeError: a is undefined

I noticed that this does not happen if I type whatever in categories backend controller, for example:

echo '';

any idea what can it be?

This issue should be examined on your server. Please PM me temporary FTP access or contact CS-Cart support team

it's on localhost. But I found that if I remove this class cm-wyciwyg from textarea (for vendor - if $runtime.company_id) the issue is solved. I'm still curious how this began to happen. Thank you anyway