I did a bunch of tests on preview network, including setting and retiring a staking pool. To my surprise, my staking pool can still mint a valid block even after it is retired. See the freshly minted block below.
Is this expected? What is the consequence of retiring a pool if it can still mint blocks? Simply not receiving rewards?
I think this explanation makes sense. That is, a retired pool can still mint blocks for another epoch since the schedule is already determined.
My experiment supports this hypothesis. For (retirement + 2) or later epochs, the active stake is shown as 0 and no leadership scheduling is given.
My experiment also shows that pool does get reward for the post-retirement blocks. You can see the pending reward for my reward account issued just a couple of hours ago