We are experiencing this same problem with SG350X series at two customers. At the first customer the issue is rare though as it doesn't occur frequently, twice in 6 months. However the second customer sees the issue each week, luckily it always occurs in the middle of the night outside of production hours. We have many more customers with these switches where we don't see this issue. The different occurrence frequency and the fact that most customers don't see this issue suggests the problem is triggered externally (I would guess a PoE device as we don't see the issue on non PoE switches)
The log entry suggests its a software bug in the switch. We have disabled Bonjour, LLDP, CDP and Auto Voice VLAN, but that does not prevent the problem from happening. The error should tell someone at Cisco with insight into the software a possible reason and possibly a possible workaround I think. The error is too cryptic for me to know what is going on. Apparently some process tries to ad an interface, but what kind of interface and to what is unclear to me.
Also I suspect the issue was introduced somewhere in the 2.3 or 2.4 firmware as the first customer did no no see this issue when they were running 2.2.x, after upgrading to 2.4.x the issue occurred for the first time.
I created a ticket at Cisco support and they first asked us to upgrade to the latest firmware, and we did. A few months later the issue occurred again and I contacted support again and they wanted me to upgrade to the latest firmware again (a new version came out between both occurrences) However the release notes did not indicate a fix for this issue, so I told them no, and send in a support package with logs etc. They looked at it and they wanted me to do a packet capture from a few seconds before the issue. However it occurs rarely and at a random time, also I don't know which of the 52 ports has the device that triggers it so I was stuck and as it was the only customer with the problem I decided to leave it and hope Cisco would fix it as I saw the CSCvo49699 bug report online.
We now have a second customer with this issue with more frequent occurrences. I will ask my colleague who is their IT contact to open a case with Cisco and hopefully they can find the issue.
