Switch port link present on empty port!

[oceanweb44]

I have 2 x 3650 stacked switches running Denali 16.3.3 that when booting are seemingly having a couple of random ports across both switches show as connected even when there is no physical connection on them. Those ports are then going into a blocked state due to STP and I'm unable to clear the block by shut / no shut in the interface.

I have now tried removing the stacking modules and the booted switches are not showing the errant port behavior on booting.

Does anyone have any idea how or why ports should come up even though there is no Ethernet connected? Any idea why the stacking modules might cause this.

I am more than a little frustrated and any assistance or advice would be greatly appreciated.

[Leo Laohoo]

Unless you find the need to, use 3.6.6 because this version has the least amount of bugs versus 3.7.X and 16.X.

[oceanweb44]

I am running the switch with 1852i APs which the earliest support is on 3.7.X so had to upgrade. As it looks like Cisco are no longer continuing with the 3.X.X software and have moved onto 16.X.X I decided we should move straight onto Denali.

If it is really the very expensive stacking modules that cause this then it would be a rather large bug and one that I would expect Cisco to have picked this up pre-release. It is not intermittent, it happens on every boot with a seemingly random number of random ports across both switches.