For some reason, the Marleybone dungeon of Kensington Park is showing up as a skeleton key team up instead of under the world. That is quite confusing!
When you try to team up for Kensington Park, you get the follow error: "Problem: You must have a wooden skeleton key in your backpack to use this sigil." As far as I know, Kensington Park has no need need for this warning, yet you can't access the team up without a Wooden Key.
Maceryn mentioned before that this error is being looked into with this wave of test realm. Hopefully it will be fixed soon, but Kensington Park has been showing up under “Key Bosses” since the SPRING ‘21 update.