[theducks]

That is NOT a Calibre conversion (or artifact).

<p><br />...
Gimmie a proper Scene break or first paragraph by using a Top Margin.
I don't even try for a 1 click repair. After EACH success, I save in case a later fix goes off the rails

Once that is done,
I fix the lowercase lowercase ones. (This is the only one I use Replace all after a few tests. I replace the Class= with the actual one used in the book

The rest I step thru Replace-Next or Find (Skips that one). These are fairly few and take only a few minutes.
Then I fix Honorifics (many have a period)
Next is Initials <I can't remember if I do the Before or After Honorifics)

Then I fix Uppercase (eg Names)

Upper-Upper is mostly for acronyms