In 4.1 with the new possessive noun feature, I'm seeing issues with words in quotations not saving correctly or not passing through the insertion to tags fully where the slug is stored but not the label/name. And some other strange behavior like saving words with quotation marks sometimes get stored with both opening and closing marks and sometimes with only opening or closing marks.
examples
'abc' <-slug (tag includes the marks)
'abc <-slug (tag includes the marks)
abc' <--ditto
And another behavior where some words I think mostly contractions but also some words ending in a closing quote are getting saved appending the letter -a.
Examples
There's -> therea
'...them' -> thema
hasn't -> hasna
I rolled back to previous version. As a related note, something I've run into working with titles with quotations, that I get titles with mixture of single,double,curly quotes. So don't know if that might help drill down.