Volume 18B: Job 38–42 has been over one year,
Vol. 32: Micah–Malachi (Revised), has been almost 2 years.
Vol. 37a: Acts 1–14, again has been almost 2 years, although I can find no evidence it has even been released.
But for the other two i can't figure out what the delay is with the other volumes.
-dan