Hola,
Thank you for your report. We are sorry for this inconvenience and we are already doing our best to fix this problem.
Please see the original post for this bug : Youtube subtitle is no longer working
To be sure that it is the same problem, can you disconnect from your youtbube account, and use the same video again with Language Reactor. It should normally work again.
Please let me know on this,
Have a good day !