Ah, that is the next problem.... Since all browsers these days seem to update/install a new version every week our Developers cannot keep up. So the PAM actually only lists a version of Firefox that we have tested with.
Odd though, the Formatting Engine in CR should be able to use those keys for Firefox as well but it is likely the tags used are not supported or correct for Firefox....
All I can suggest is try the next patch and see if that works...
The other work around is to make sure the text objects do have enough space to compensate for the various browsers...
Edit the object and under the Paragraph tab add a .7 to the right margin, that is the lowest that we can use to offset the font reduction. It may cause the text to push to the next line so Can Grow may need to be checked on or set to 1 also.
Don