Thanks Alex, I cleared the cache and switched the forum skin back to mobile and it stopped this happening.
The ad issues are something I get around, and could with a blocker anyway, so I wouldn't be entertaining you changing it to work without JavaScript as it's very useful. It's only that edit issue that seems to be a problem and that has only appeared since the upgrade so I expect that just one of the buggy issues to sort out. I've been using both formats and I think they both work better on a small screen mobile than the previous version, even with the ads it's less of an issue than it was. The upgrade is well worth it.