v3 dequeue times have been greatly improved and we're now seeing sub-500ms p50 dequeue times (it was previously 10-20s p50 dequeue times). We ended up backporting all of the dequeue performance improvements we made in v4 and even made some improvements that we'll be bringing to v4 soon as well.

We are experiencing slower than normal dequeues on v3. We're actively investigating why this is happening. Runs are still executing but they're being pulled from the queue much slower than usual.