Unable to remove Static Drop entry | 2960 Cam Table

Question

Hi all,
I am facing a strange issue here on a production switch (Cisco 2960 IOS 12.2(55)SE5)
I have the following entry in my cam table:
switch#show mac add int gi0/10
          Mac Address Table
Vlan    Mac Address       Type        Ports
123    1234.1234.1234 STATIC      Drop
Although this mac-id has not been statically entered in any way it shows up as static and I can't remove it. I tried all possible clear commands without success. As a last step I reset the interface to the default empty config just configuring it as access port in an office vlan.
I am trying to avoid having to reload the switch to clear the related memory as this generates downtime. Has anyone ever faced such an issue and can advise me?
Logs:
switch#show mac add add 1234.1234.1234
          Mac Address Table
Vlan    Mac Address       Type        Ports
123    1234.1234.1234    STATIC      Drop <-- note the "interface"
Total Mac Addresses for this criterion: 1
Current configuration : 47 bytes
interface GigabitEthernet0/10
shutdown
end
switch#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
switch(config)#int gi0/10
switch(config-if)#sw mod ac
switch(config-if)#sw ac vl 123
switch(config-if)#no sh
switch(config-if)#do sh mac add int gi0/10
          Mac Address Table
Vlan    Mac Address       Type        Ports
123    1234.1234.1234    STATIC      Drop
Total Mac Addresses for this criterion: 1
switch(config)#clear mac address-table static 1234.1234.1234 vlan 123 drop
MAC address could not be removed.
Address is not user configured
switch#clear mac add dynamic address 1234.1234.1234
switch#sh mac add add 1234.1234.1234
          Mac Address Table
Vlan    Mac Address       Type        Ports
123    1234.1234.1234    STATIC      Drop
Total Mac Addresses for this criterion: 1

Answer 1

Hi Umesh,
Of course there is nothing with this mac in the config. That was like the first thing that has been checked. There was dot1x running on this and all the other ports which of course has been disabled and cleared accordingly.
The problem is that there is some sort of cam table holding the Drop entries and although it should the memory is not being freed up when using the commands according to the documentation.
This is definitely a question for an IOS geek or someone who already had a similar issue once. If I open a TAC case they will tell me to reboot so the only hope is really someone who had this issue already once and resolved it without reboot.
Anyone with experience in this?