Multiple Cisco C1000L and 2960 LED link lights all blink in slow unison

[MMSIT]

We recently swapped out some older Adtran switches for new Cisco C1000Ls. We also have a second stack that has a couple of Cisco 2960s not stacked or connected through the C1000Ls at all. Sometime after finalizing all the connections from old to new, we noticed that ALL switches interface LED status lights all are blinking at the same slow rate in unison. This happened to both stacks at approx the same time and this was not noticed behavior prior to the updates. Each switch has 1 VLAN each and each interface are all in Access mode for end user workstations. No switch to switch connections on this stack. They all have 1 for 1 gigabit uplinks SFP back to our router. This is odd behavior because its a very slow blink, maybe once every 2 seconds. Every switch blinks at same rate unless one gets rebooted then that ones timing is slightly off but same behavior, all slow blink. If all blinking very fast at the same rate, Id suspect broadcast storm. But that is not being observed. Ive seen similar posts talking of the same for fast blinking but nothing for slow unison blinking on 2 different sets of Cisco switches in 2 separate stacks.

Any feed back is much appreciated to help me understand this odd behavior. 

[balaji.bandi]

before come to "slow rate in unison" LED Blinking, when the device connected to this switch have any performance issue, lost connection ? or any user complaints?

Console to both the switches and Look at the Live logs, or issue show logging  (if enable to see the Logs ) - post complete logs when that happened to understand?

Hope there is not Spanning tree Loop in the network?  what kind of cable is this Cat 5 or cat 6?

[MMSIT]

No issues are being reported by end users after UDP relay for DHCP was corrected at the router.  Only errors I truly see are interfaces going up and down when connected to devices that do not disconnect from or go offline at the rate in which it seen in the Web GUI console logs.  On this particular switch, Interface 1/0/32 seems to show up the most but its random on which ports do an do not have this behavior. It appears this occurs with most of the connected ports.

2021-00-21 16:55:22.725 LINK 3 Interface GigabitEthernet1/0/6, changed state to down UPDOWN
2021-00-21 16:55:25.739 LINK 3 Interface GigabitEthernet1/0/6, changed state to up UPDOWN
2021-00-21 16:55:26.739 LINEPROTO 5 Line protocol on Interface GigabitEthernet1/0/6, changed state to up UPDOWN
2021-00-21 16:55:40.697 LINEPROTO 5 Line protocol on Interface GigabitEthernet1/0/6, changed state to down UPDOWN
2021-00-21 16:55:41.697 LINK 3 Interface GigabitEthernet1/0/6, changed state to down UPDOWN
2021-00-21 16:55:44.637 LINK 3 Interface GigabitEthernet1/0/6, changed state to up UPDOWN
2021-00-21 16:55:45.637 LINEPROTO 5 Line protocol on Interface GigabitEthernet1/0/6, changed state to up UPDOWN
2021-00-21 17:03:22.965 LINEPROTO 5 Line protocol on Interface GigabitEthernet1/0/32, changed state to down UPDOWN
2021-00-21 17:03:23.966 LINK 3 Interface GigabitEthernet1/0/32, changed state to down UPDOWN
2021-00-21 17:03:26.879 LINK 3 Interface GigabitEthernet1/0/32, changed state to up UPDOWN

Which CLI logs would you like to see? A show tech-support bundle?

I am trying to rule out a STP loop or a Broadcast storm of some sort. 

The network drops are Cat5e and Cat6 with all Cat6 patch cables between switch and patch panels. Likewise at end user side, Primarily Cat6 patch cables with a few Cat5e

[MMSIT]

Him thanks for replying. I was thinking a technical error of some sort also. Although, I am not sure I follow what you are suggesting to do. When you say install all settings, is there a document you can share that shows those settings? 

Spanning tree is enable, each interface is configured as access ports with port fast enable, but storm control is not enabled for each port. Are you maybe referring to this as a missed setting?

Please advise of any CLI logs or config you would like to see and I'll be happy to provide what I can.

[balaji.bandi]

post complete config - show run, show spanning-tree brief, show spanning-tree block (outputs)

this up down could be speed mismatch or loose contact, what is the device, what speed nic it got ?

2021-00-21 16:55:22.725 LINK 3 Interface GigabitEthernet1/0/6, changed state to down UPDOWN
2021-00-21 16:55:25.739 LINK 3 Interface GigabitEthernet1/0/6, changed state to up UPDOWN

[MMSIT]

Hi, thanks for responding.   I am attaching the requested CLI commands from the switch we feel at fault (Switch 2 Putty logs) and its neighbor switch as well. I have redacted all usernames, passwords, RSA keys, private keys, IPs and MAC addresses. 

Looking at these logs, I don't see a problem, but please do have a look and let me know if we need to collect anything more. 

I can confirm there is a speed mismatch on port 1/0/1 and we are fairly sure that this is due to either a break in the line or a lose wire. But we never see 1/0/1 going up and down. So when we see these other ports doing it constantly, it has us a little confused. Those end users are 1Gb work stations. With 1Gb switch. The entire stack is a gigabit network. 

Look forward to hearing your response.