Same here. Two iOS submissions have been in Waiting for Review since 3 September — seven days now — with no messages and nothing flagged. For what it's worth, there are threads from February with the same pattern: waits of 8 to 20 days, all stuck in Waiting for Review rather than In Review. One developer there reported a submission from 9 February moving to In Review after 15 calendar days, then getting feedback 6 minutes later — so the delay seems to be entirely queue time, and the review itself is quick once it starts.