uBlock Origin - Windows vs Lubuntu

[Quatermass]

I run Firefox with uBlock Origin on both Windows and Lubuntu. Same versions of FF (55) and uO (1.14.10), same uO settings. Any ideas why the rather intrusive ads now being served by the Guardian (e.g. sometimes at the top of their page) seem to be successfully blocked on Windows but not on Lubuntu?

[Quatermass]

Fixed by a uO reinstall.