MPC-HC Can't See Embedded SRT Subtitle Track

I'm having a strange issue with MPC-HC where it will not see the embedded SRT subtitle track within the file, when I right-click the "Subtitle Track" option appears to be greyed out, VLC player has no such issues along with my hardware-based players, here is a short 1 min sample https://www.mediafire.com/file/rlqk9t77y0kn5ox/The_Legend_of_Black_Charley_1972.zip/file

This usually means that the subtitle track was muxed incorrectly and marked as disabled, which means it should be hidden. You can fix this by remuxing the file with MkvToolNix. Then you can re-enable the track.

The behavior of VLC is incorrect!

I feel like a complete idiot, for whatever reason it seems to have been an issue with all versions of MKVToolNix prior to v77.0, the subtitle track is disabled when a file is imported, why that was the case, who knows, anyway it was this bug fix in v77.0 that had rectified the situation.

MKVToolNix GUI: multiplexer: the GUI will now check the state of the 'track
 enabled' flag of all video, audio & subtitle tracks when starting to
 multiplex or adding a job to the job queue. If there's no track with its
 flag turned on for a type, the GUI will turn on the flag for the first track
 of the type. This behavior can be turned off in the preferences. Implements
 #3535.