With SOLR in place, search results are still sorted by modified date.

It is an issue with https://github.com/ezsystems/ezplatform-kernel/blob/master/eZ/Publish/Core/Repository/SearchService.php#L347
"searchHandler" will never be an instance of Capable. As it is type-hinted "eZ\Publish\SPI\Search\Handler" and has "lazy: true"