Can confirm the same issue. Tested the video w/o outputting to Chromecast and it works fine with subtitles.
I have a logcat of the run trying to send to chromecast linked below though I believe the issue might be related to these
02-10 18:48:33.269 W/VLC/medialibrary( 2664): ../src/MediaLibrary.cpp:347 virtual MediaPtr medialibrary::MediaLibrary::media(const std::string &) const Failed to create FS factory for path smb://FREEDOM/D/temp/%5BErai-raws%5D%20Boku%20no%20Hero%20Academia%20S2%20-%2000~25%20%5B1080p%5D%5BMultiple%20Subtitle%5D/%5BErai-raws%5D%20Boku%20no%20Hero%20Academia%20S2%20-%2012%20%5B1080p%5D%5BMultiple%20Subtitle%5D%5BF16D1FB0%5D.mkv
02-10 18:48:34.412 D/VLC ( 2664): [8fc770b0/d6f] libvlc stream output: adding a new sout input for `ssa ` (sout_input: 0x92359838)
02-10 18:48:34.412 E/VLC ( 2664): [8b6084b0/d6f] libvlc stream out: unknown stream ID
02-10 18:48:34.412 E/VLC ( 2664): [82f96ab0/d6f] libvlc decoder: cannot continue streaming due to errors with codec ssa
02-10 18:48:34.765 I/VLC/VideoPlayerActivity( 2664): remove View!
02-10 18:48:36.117 D/VLC ( 2664): [8b6084b0/d4e] libvlc stream out: paused state
02-10 18:48:36.117 D/VLC ( 2664): [901695b0/d54] libvlc decoder: toggling resume
02-10 18:48:36.118 D/VLC ( 2664): [90169830/d55] libvlc decoder: toggling resume
02-10 18:48:36.118 D/VLC ( 2664): [82f96ab0/d6f] libvlc decoder: toggling resume
02-10 18:48:36.120 D/VLC ( 2664): [8d563070/d53] libvlc stream: pausing
02-10 18:48:36.131 D/VLC ( 2664): [8b6084b0/d51] libvlc stream out: Player state: PAUSED sessionId: 1
Logcat
https://hastebin.com/uvedajicit.pl