Re: RSTP issue with ex4300 and ex2300 in 18.4 version
When the root bridge has more than one port on a single LAN segment, the bridge ID is effectively tied, as are all root path costs (all equal zero). The designated port then becomes the port on that LAN segment with the lowest port ID. It's put into Forwarding mode while all other ports on the root bridge on that same LAN segment become non-designated ports and are put into blocking mode
Please check if this is the situation you are facing, if yes, this is expected.
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