Find highlighting stopped working

[maertsoi]

I was editing 8 out of 9 books with no issues, after closing book 8 and opening book 9, my Find highlight is no longer working. (Continues to work in all the others).

Regex: [[:digit:]]{4}-[[:digit:]]{1,2}

Example text:

1902-1
Useless text goes here blah blah
Useless text goes here blah blah
Useless text goes here blah blah 
Useless text goes here blah blah
1902-2
Useless text goes here blah blah
Useless text goes here blah blah
1902-3
Useless text goes here blah blah
Useless text goes here blah blah
1902-4
Useless text goes here blah blah
Useless text goes here blah blah
1902-5
Useless text goes here blah blah
Useless text goes here blah blah
1902-6
Useless text goes here blah blah
Useless text goes here blah blah

Find settings: Regular Expression, Wrap, Highlight Matches

If I click Find or Find All, everything still highlights ok. But if I click back into the text file (.txt), it all goes away.

Image, right: you can see the highlight is still persistent
Image, left: nothing

Attempted reopening apps, restarting, git refresh, PersistentRegexHighlight (oh god the lag.)

[maertsoi]

Appears to have been some kind of file size or line count limitation. I split the file into two, and it is working properly.

Any thoughts on what it was?

[bschaaf]

See the find_highlight_matches_max_size and find_regex_highlight_matches_max_size settings and their associated comments.