mkvpropedit not resizing EBML Voids inside CloneBD-generated subtitle Tracks
When CloneBD generates subtitle tracks it generates extra tracks for possible forced subtitles and then "deletes" them by overwriting unused tracks with EBML Voids. mkvpropedit appears to be keeping these voids rather than resizing them - so if a tag is added, mkvpropedit moves the tracks to the end of the file (which breaks Windows). If a tag is shrunk - e.g. change subtitle Name from "English" to "F" then mkvpropedit adds its own new EBML Void - which appears to be outside the Track structure - see example below at Track number 6/UID 6.
E.g. original CloneBD output file
| + Track
| + Track number: 3 (track ID for mkvmerge & mkvextract: 2)
| + Track UID: 3
| + "Lacing" flag: 0
| + Name: English
| + Language: eng
| + "Default track" flag: 0
| + Codec ID: A_AAC
| + Track type: audio
| + Audio track
| + Channels: 2
| + Sampling frequency: 48000
| + Bit depth: 16
| + Codec's private data: size 5
| + Track
| + Track number: 4 (track ID for mkvmerge & mkvextract: 3)
| + Track UID: 4
| + "Lacing" flag: 0
| + Name: English
| + Language: eng
| + "Default track" flag: 0
| + Codec ID: S_HDMV/PGS
| + Track type: subtitles
| + EBML void: size 55
| + Track
| + Track number: 6 (track ID for mkvmerge & mkvextract: 4)
| + Track UID: 6
| + "Lacing" flag: 0
| + Name: English
| + Language: eng
| + "Default track" flag: 0
| + Codec ID: S_HDMV/PGS
| + Track type: subtitles
| + EBML void: size 58
File after changing name to "F" via mkvpropedit:
| + Track
| + Track number: 2 (track ID for mkvmerge & mkvextract: 1)
| + Track UID: 2
| + "Lacing" flag: 0
| + Name: English
| + Language: eng
| + Codec ID: A_AAC
| + Track type: audio
| + Audio track
| + Channels: 2
| + Sampling frequency: 48000
| + Bit depth: 16
| + Codec's private data: size 5
| + Track
| + Track number: 3 (track ID for mkvmerge & mkvextract: 2)
| + Track UID: 3
| + "Lacing" flag: 0
| + Name: English
| + Language: eng
| + "Default track" flag: 0
| + Codec ID: A_AAC
| + Track type: audio
| + Audio track
| + Channels: 2
| + Sampling frequency: 48000
| + Bit depth: 16
| + Codec's private data: size 5
| + Track
| + Track number: 4 (track ID for mkvmerge & mkvextract: 3)
| + Track UID: 4
| + "Lacing" flag: 0
| + Name: English
| + Language: eng
| + "Default track" flag: 0
| + Codec ID: S_HDMV/PGS
| + Track type: subtitles
| + EBML void: size 55
| + Track
| + Track number: 6 (track ID for mkvmerge & mkvextract: 4)
| + Track UID: 6
| + "Lacing" flag: 0
| + Name: F
| + Language: eng
| + "Default track" flag: 0
| + Codec ID: S_HDMV/PGS
| + Track type: subtitles
| + EBML void: size 58
|+ EBML void: size 4
Note that mkvpropedit added its own EBML of size 4 rather than growing the one of size 58. Likewise if the name is changed to something with more characters than the original, mkvpropedit re-creates the track, retaining the size 58 EBML Void.