User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:46.0) Gecko/20100101 Firefox/46.0 Build ID: 20160421124000 Steps to reproduce: Try this text, for example: Ităque quantumcumque itinĕris equitātu efficĕre potĕrat, cotidie progrediebātur, et legiōnem unam minorĭbus itinerĭbus subsĕqui iussit. Actual results: The diacritics above some letters are moved to the right, I can see it while I'm writing this message, try it also with "Palatino Linotype" font. It is moved in Firefox, but in Google Chrome it's ok. Expected results: The diacritics should be right above the letters. Compare Firefox and Chrome results.

Could you attach a testcase with the font and the text, please.

Add a testcase to http://codepen.io/ lease.

I've added the screenshots, the text (the additional is below also), "Palatino Linotype" font, if needed, is in your system font folder. Tullia puella Romāna est. Terentia matrōna Romāna est. Terentia mater Tulliae est. Iulia, Aemiliae filia, Tulliae amīca est. Terentia Syram vocat: «Syra! Tulliae tunĭcam novam da!» «Quo propĕras, Tullia?» — Syra rogat. «In silvam cum amīcā propĕro», — respondet Tullia.

(In reply to Loic from comment #4) > Add a testcase to http://codepen.io/ lease. I don't see anything about a testcase and how it's connected with Mozilla and so on. As a good user I reported two bugs and go to sleep :)

This is another example of the same issue described in bug 1269484: the font involved does not actually support the combining marks here. The Chrome rendering is a result of applying NFC normalization.