Satoshi said... Ok, I figured it out. Sorry for making you try to reproduce it, it's actually the fault of the "Transform on'yomi readings into katakana" userscript.Thanks! I didn't use that script so I couldn't reproduce it. I'll install it to try and fix (or at least work around) the incompatibility. Or does the script actually cause problems without mine?
When I disable it your script works fine.
EDIT: Just tested it, the problem only occurs on Chrome, but the kana still disappear even with my script disabled. Not my fault, then!