Issue #3295790 by bradjones1, mstrelan, rpayanm, catch, alexpott, acbramley,...

Issue #3295790 by bradjones1, mstrelan, rpayanm, catch, alexpott, acbramley, longwave, kim.pepper, mfb: Post-response task running (destructable services) are actually blocking; add test coverage and warn for common misconfiguration