It's not a bug.
It's a problem on how blender shows the numerical values in some places (like in spin tool), if you do the spin manually and you see 360°, there is a hidden decimal value that prevent the automerge, if you hit on it and delete this decimal, the automerge happens.

Well, here it works fine.

• select a face
• enable spin tool
• rotate 360 degrees while holding ctrl to snap
• enable Auto Merge

It works.

If it fails, please give a specific example of how? For me it seems to work just fine.

Good point @William Reynish (billreynish).

I think it will be better to have a little bit higher merge value and a setting for this to avoid it....decimal explanation is quite good for experts ^^

ok I will try later with ctrl again william but automerge should be enough. here is the exact situation around 2'30 quick pyramide using spin tool

(just total different thing but I just did this. integrated to blender it will be good for average users [[ https://www.youtube.com/watch?v=_PjB1KQTqSc&t=72s| fast hdr settings]]https://www.youtube.com/watch?v=_PjB1KQTqSc&t=72s
that's a shame that in nodegroups it's not possible to integrate parameters without entries, in input or output, as a directory path of an image node, or the setting in mapping node. I wanted to put all in a node to have the setting all together in the properties menu on the right)

so it will be good to indicate the snap in the information windows or a little text as press "ctrl to merge" as an information. like it's a tool I thought was really auto.
other point a possibility to select no tool would be a good point

@-- (zgorg):
I still don't see the issue. I tried to first rotate to 360 degs, enable Auto Merge and then change the steps value. It still works.

Please provide an exact list of steps to reproduce the issue.