I am seeing conflicts when trying to use tasks with semantic mediawiki 1.6 and higher. This all seems to circle around SMW's use of the validator extension, as this is the point it joined the code. Is anyone else having these issues? Mediawiki 1.18.2 or 1.19 vanilla on an empty wiki doesn't make any difference, but if I use SMW 1.5.6 tasks works fine, but anything 1.6 and above gives no task emails (no errors either). Putting debug breadcrumbs in the code suggests that the SMW query that tasks calls leads to the "assigned to" response being the pagename rather than the text/username following the "assigned to" text.
I shall play around with the code, looking at the diffs that occurred between 1.5.6 and 1.6 in SMW_QueryProcessor.php, as I am happy to hack my own installation to get this working rather than waiting for a release.