We have a node, which has an alias "/foo/bar". We also have a view in path "/foo".
Sometimes page cache ends up showing contents of the view in the url "/foo/bar". We can fix the situation by rebuilding caches, but after some time the path is pointing into the wrong route again.
We've noticed only one specific node, which behaves this way, even though we have many nodes with a similar path. We have checked the alias and the alias seems perfectly normal.
When looking at the cache_data table, we can see that when this situation occurs, this route is saved by the path "/foo/bar" and not by the "/node/123" path, which would be the normal case with all the other similar nodes.