Yes, but they can't do anything about it anyway. The FSF resolution on this matter, though, essentially means that they might just as well pull Euro-Office patches into OnlyOffice. So in the end, the product will be formed by combined effort.
The codebase will diverge quickly; the Russian one is heavily obfuscated with s ton of Russian in it and obscure commit messages. A large portion of prep work by Nextcloud was cleaning and translating. OnlyOffice was also known for refusing PRs, too.