I installed node-red-contrib-chatbot
There are many nodes in this package.
No nodes were added to flows at this stage yet.
I disabled them all, they disappear from palette as expected.
Enabled a couple of them - they do not appear in the palette.
Closed the palette "manager" sidebar and reopened it
Enabled some more nodes, they started to show up.
Build some flows with these nodes, working nicely.
Restarted node-red (for other reasons).
The nodes were now "missing" in the flows (node-red started normally without error):
I cannot disable the nodes, nor enable others.
I cannot remove the complete package because it ends up with an error "node in use"
In the configuration tab there is nothing used/unused related to this package.
Have you tried group/drag selecting all the nodes (visible on edit screen) and deleting them (delete button) deploying then opening the config and looking for the config node assiciated with those nodes?
Delete it then remove it from the palette manager.
Install node-red-contrib-chatbot, disable all nodes, enable some, they won't appear in the palette.
Close the "palette panel", reopen it, enable some more, they show up.
Add some nodes to a flow, deploy.
Restart nodered, nodes show up as unknown.