Last modified: 2011-04-14 21:55:04 UTC
The wikitext a<sub>b''</sub> should not be subscript is translated to the HTML <p>a<sub>b should not be subscript</sub></p> on the English wikipedia. If $wgTidy is turned off, it yields wrongly nested tags: <p>a<sub>b<i></sub> should not be subscript</i>
This seems to be fixed now; see the URL.
Still broken as of r24945. Tidy may be handling it better, but we still get incorrect nesting out of MW.
Fixed since. Current output: <p>a<sub>b</sub> <i>should not be subscript</i></p>