gleam: Agent log crammed with CollectExecutionStatistics(_) error

excerpt from the log file:

2017/08/22 23:13:40 &{0xc420274000}.CollectExecutionStatistics(_) = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:40 &{0xc420252000}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:40 &{0xc4201be1c0}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:40 &{0xc4201b21c0}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:40 &{0xc420130700}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:40 &{0xc4201561c0}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:40 &{0xc4201ba1c0}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:40 &{0xc420274000}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:40 in memory 5:1 finished writing f1213273487-d5-s1 0 bytes 2017/08/22 23:13:40 in memory 6:0 finished reading f1213273487-d5-s1 0 bytes 2017/08/22 23:13:40 &{0xc420388000}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:40 &{0xc42009c540}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:40 in memory 5:6 finished writing f1213273487-d5-s6 0 bytes 2017/08/22 23:13:40 in memory 6:0 finished reading f1213273487-d5-s6 0 bytes 2017/08/22 23:13:40 in memory 5:9 finished writing f1213273487-d5-s9 0 bytes 2017/08/22 23:13:40 in memory 6:0 finished reading f1213273487-d5-s9 0 bytes 2017/08/22 23:13:40 &{0xc4201fe380}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:40 in memory 5:11 finished writing f1213273487-d5-s11 0 bytes 2017/08/22 23:13:40 in memory 6:0 finished reading f1213273487-d5-s11 0 bytes 2017/08/22 23:13:40 &{0xc420374000}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:41 deleting f1213273487-d5-s6 2017/08/22 23:13:41 deleting f1213273487-d5-s11 2017/08/22 23:13:41 deleting f1213273487-d5-s1 2017/08/22 23:13:41 deleting f1213273487-d5-s9 2017/08/22 23:13:46 in memory 5:5 starts writing f1750670629-d5-s5 expected reader:1 2017/08/22 23:13:46 &{0xc42034c000}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:46 in memory 5:1 starts writing f1750670629-d5-s1 expected reader:1 2017/08/22 23:13:46 &{0xc4202a6000}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:46 &{0xc420130380}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:46 &{0xc420230000}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:46 &{0xc4201c81c0}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:46 &{0xc4201ca1c0}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:13:46 in memory 6:0 waits for f1750670629-d5-s1 2017/08/22 23:13:46 in memory 6:0 start reading f1750670629-d5-s1 2017/08/22 23:13:46 in memory 6:0 waits for f1750670629-d5-s5 2017/08/22 23:13:46 in memory 6:0 start reading f1750670629-d5-s5 2017/08/22 23:15:15 &{0xc42014e1c0}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:15:15 &{0xc4201c8540}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:15:15 &{0xc420278000}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:15:15 &{0xc42023a000}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:15:15 in memory 5:5 finished writing f1750670629-d5-s5 0 bytes 2017/08/22 23:15:15 in memory 6:0 finished reading f1750670629-d5-s5 0 bytes 2017/08/22 23:15:15 in memory 5:1 finished writing f1750670629-d5-s1 0 bytes 2017/08/22 23:15:15 in memory 6:0 finished reading f1750670629-d5-s1 0 bytes 2017/08/22 23:15:15 &{0xc420380000}.CollectExecutionStatistics() = , rpc error: code = Unavailable desc = grpc: the connection is unavailable 2017/08/22 23:15:15 &{0xc42009c1c0}.CollectExecutionStatistics() = _, rpc error: code = Unavailable desc = grpc: the connection is unavailable

My application gives me unexpected result running in distributed mode which consists of 4 agent nodes. If I run it with local master and agent, everything seems fine. Not sure if this sort of error is related. 2017/08/22 23:15:15 &{0xc42014e1c0}.CollectExecutionStatistics(_) = _, rpc error: code = Unavailable desc = grpc: the connection is unavailable