Confusing wording on "leave group" confirmation form

When you leave a group, the user interface text on the confirmation form is confusing and inconsistent. On the current site it looks like this:

But on the staging site it looks like this:

My concerns:
- The phrase "This action cannot be undone" is incorrect. You can join a group again after you left it.
- The are-you-sure question asks if you want to "unsubscribe", but the original "leave" is more appropriate.
- The button is labeled "remove". This should be the same word as used in the are-you-sure question, so preferrably "leave", or at least "unsubscribe".