Hey Man,
Thanks for reaching out and apologies for taking a while to reply.,.
There is one bug we know of on Beta 4.2 where subtitles don't show at all... It normally happens on Windows 8 or 7, so if that describes your issue, no worries- we're working on fixing it and it should be fixed by the next update beta 4,3 which will be released soon!!
If this doesn't fit your situation, please let us know more details regarding your issue so we can check it out.
Thanks and apologies for the inconvenience.