what is the mode of your AP? Local or anything else?
Having APs talk to WLC in a tunnel, AP sends to WLC from one Mac address and clients Mac addresses should be included inside the tunnel.
Is the affected port directly connected to the AP or or is connected to the Switch to which the AP is directly connected?
Having 1230 APs a bit old, this could possibly bug of compatibility but this needs more investigation to verify. We need to know what are the Mac addresses that cause the problem and what is the source.
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