[Sirtel]

Conversion really has not changed all that much, so I doubt just reconverting would help, unless you changed the conversion settings. You could always try with a few known culprits first.

While I do use conversion instead of Kindle Unpack (I prefer it this way), I have several customized settings AND I edit any formatting issues manually in the calibre editor.

I don't check for errors. Converting fixes some of them and I've found that very few of my converted and edited books actually need error checking. So I don't bother.