sick thunder
Not sure if this is a bug, but if this is working as intended, then there should be something to say that. It doesn't have the "Permanent" keyword(Which I'm pretty sure I saw on another location, but it's not in the glossary), and there is nothing in the description of "Anomaly" that says it cannot be replaced.
upper violet
Anomaly is the keyword indicating that location can only be played on opponent's lanes.
I think the location there is Murasaki 312, and if so it is not intended to be replaceable (since it was played against you). We're taking a look at the messaging which is the bug.