Problem with setting "Beautify individual files automatically when they are opened"?

[Capricorn]

Hi everybody,

Calibre v4.12
Windows v1909 with the latest updates.

For the past day or two I observed the following:
Normally, on opening an epub book with the calibre editor, I would run the "check book" function. If any errors appeared eg. text-indent is present multiple times, I would click on that error message, so that the editor would take me to the proper place in the stylesheet where the error was. That was the way the calibre editor had always worked so far.
But now, it would sometimes jump to a location in the stylesheet, that had nothing to do with the place where the error was. It would sometimes be a few lines off, sometimes many lines, and sometimes I could not find the error at all (eg rule is empty), even when I went through the stylesheet line by line.

As I have a very old computer, at first I thought it was the computer going belly up, but looking at the event viewer and the log files did not give any info.
Checking my harddrive for errors did not produce any errors.
Looking at the date of the latest windows update did not provide a clue, as I was 95% the problem occurred later.

I then remembered that I had changed the settings in the calibre editor: I had activated the setting "Beautify individual files automatically when they are opened".
Searching in the forum on "beautify files" did not provide any clues.

When I deactivated this setting, everything turned back to normal. Clicking on an error message after "check book" brought me to the correct place in the stylesheet.
I could observe this properly on clicking on the error message "rule is empty". If the above setting is deactivated, it finds this place correctly, and I can remove it. However, if the setting is activated, the "beautify" function removes the empty rule, but check book still believes it is there. And hence tries to jump in the stylesheet to the place where the empty rule was.
Hence I assume that "check book" still works on the original epub, ie BEFORE beautifying it, and not afterwards. In other words it does not seem to take into account the changes "beautify" has made.
Also, it does not matter which epub I take.

So, my question is: Does anyone else observe this? And is my theory as to what goes wrong correct? Or is it simply me and my computer(usually)?

[theducks]

Yes! I have seen the Jump to wrong/random? place issue. (Different than a Not found, which lands at line 1) There seemed to always have been cases that this happened (after edits). Save and exit settlrd out that book, Now it seems more frequent.

Beautify on open is NOT set in my case.
The clean unused tags will not fix the 'empty rule IF there is a comment INSIDE it.

[kovidgoyal]

check book works on the book files. Beautify when open beautifies when the file is opened for editing, which will typically happen after check book. Henace the mismatch. If you want to use beautify on open and check book you should run beautify all fies before running check book.

[Capricorn]

Ah...very good to know. It simply means, that if I adapt my workflow ie first beautify all files, then check book, and not vice versa the way I have always done, it can work with the setting activated. Easy.
Thank you.