See the screenshot

Search highlightings end after 22003 line, no highlights on 22014 and for next.
Seems it isn't a bug, but it was so unexpected, I'd prefer it for my task.
Hello @RomanLT ,
Standard the maximum occurrences is limited to "2000 occurrences"
To bypass this, go in Notepad3.ini --> Settings2 --> Uncomment this key and modify the value : ;MarkOccurrencesMaxCount=2000

This limiting setting has been deprecated in current (release) version, so it should not happen.
Reason for deprecating: The Focused-View feature (and correlated Bookmarking of Occurrence Indicators).
(Disadvantage: In very long text files, the Occurrence Indicating will take some time - switching to "Match Visible Only" will help in that case).
Yes, "Notepad3 (x64) v5.20.915.1" is good about it. And 10000 occurences seems invisibly fast.
Thanks!
I was previously changing this setting to 30000 with no noticeable performance impact.
Standard the maximum occurrences is limited to
"2000 occurrences"
To bypass this, go in Notepad3.ini --> Settings2 --> Uncomment this key and modify the value :;MarkOccurrencesMaxCount=2000
This limiting setting has been deprecated in current (release) version, so it should not happen.
I was previously changing this setting to 30000 with no noticeable performance impact.
As @RaiKoHoff noted above, the key MarkOccurrencesMaxCount=2000 has been removed from: Notepad3_5.20.822.1_beta
Most helpful comment
This limiting setting has been deprecated in current (release) version, so it should not happen.
Reason for deprecating: The
Focused-Viewfeature (and correlated Bookmarking of Occurrence Indicators).(Disadvantage: In very long text files, the
Occurrence Indicatingwill take some time - switching to "Match Visible Only" will help in that case).