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Modbus TCP with [RST] Flags

Hi, I have few controllers (one main and 6 auxiliaries) communicating on Modbus TCP. The main controller is on and the auxiliaries are in the range One of the auxiliaries can not communicate with master. On Wireshark, I am getting [TCP Out-Of-Order] followed by [TCP Dup Ack], [TCP Retransmission], and finally [RST] flags at the end of some streams. This issue is only happen for one of the controllers. In this case, the one on ip: The timeout is set to 1000 ms on controllers.

If I reupload the code on the main, one randomly selected auxiliary will have the above issue. If I reupload the program on auxiliaries, the controller which is updated the last will have this issue. For example, If I re-upload on auxiliaries #1,2,3,4,5,6 in order then #6 will have the error. If reupload on auxiliaries in order #5,3,4,6,1,2 then #2 will have the error.

Any idea what could cause this issue?