It might be problem with highlighting but would be useful to receive a document or a part document to reproduce.
I have checked an html5 example for https://html5example.com/ with find next/prev misspelings while language in Notepad++ set to HTML, seems to work ok

When I choose "Find Next Misspelling" in an HTML 5 document, either from the menu or an assigned hot key, it incorrectly reports various HTML tags and (sometimes strings, which it should be ignoring) as misspelled. For example:

• src
• ul
• html

Aside from being false positives, the reported words are highlighted in a different color (green) than valid mis-spellings (pink).

Am I doing something wrong, or is this a bug?

Debug info:

Notepad++ v8.7 (64-bit) Build time : Sep 17 2024 - 17:06:31 Path : C:\Program Files\Notepad++\notepad++.exe Command Line : "C:\Users\Dick\Documents\tch\site\htm\c\a\r\o../../../../../bio/y/a/l/e/yale_ed.htm" Admin mode : OFF Local Conf mode : OFF Cloud Config : OFF Periodic Backup : OFF OS Name : Windows 11 Pro (64-bit) OS Version : 23H2 OS Build : 22631.4317 Current ANSI codepage : 1252 Plugins : DSpellCheck (1.5) mimeTools (3.1) NppConverter (4.6) NppExport (0.4)

I think it should be on the same e-mail chain, but here I'm quoting your original post, sorry for not replying sooner.

Ignore my earlier e-mail about a bad memory. I found this on GitHub (obviously).

I have a later version of Notepad++ than when I first submitted this last October, and cannot reproduce the problem, so perhaps whatever Notepad quirk triggered the behavior been fixed.

My latest sysinfo:

Notepad++ v8.7.5 (64-bit)
Build time : Dec 21 2024 - 05:13:03
Path : C:\Program Files\Notepad++\notepad++.exe
Command Line :
Admin mode : OFF
Local Conf mode : OFF
Cloud Config : OFF
Periodic Backup : OFF
Placeholders : OFF
DirectWrite : OFF
Multi-instance Mode : monoInst
File Status Auto-Detection : cdEnabledNew (for current file/tab only)
Dark Mode : OFF
OS Name : Windows 11 Pro (64-bit)
OS Version : 24H2
OS Build : 26100.2894
Current ANSI codepage : 1252
Plugins :
ComparePlugin (2.0.2)
DSpellCheck (1.5)
mimeTools (3.1)
NppConverter (4.6)
NppExport (0.4)

I think we can declare this one fixed. Although, as I used to say when I worked in software support, “Problems that go away by themselves tend to come back by themselves” 8=).