Task org.apache.jackrabbit.oak.commons.concurrent.NotifyingFutureTask@51fb9ba5[Not completed, task = org.apache.jackrabbit.oak.spi.commit.BackgroundObserver$1$1@55c405c5] rejected from java.util.concurrent.ThreadPoolExecutor@14f90ffe[Shutting down, pool size = 1, active threads = 1, queued tasks = 0, completed tasks = 2]