Yup, it is really weird but that’s how it is. When you hit “release” the page reloads but there is no change or indication that anything happened within the dashboard. Even the details for that specific version, within the version summary section will remain on “approved.” As for the screenshots, I am fairly certain that they will only be included in the version if:
(A) You uploaded them while the version was in the testing phase.
(B) You uploaded them while the version was not within the testing phase, but later reverted back to testing at some point before submitting for review
When you move to a hosted test, it basically bundles all the extension data together (frontend files, summary, description, screenshots, contact email, etc), and that same bundle is what is used during review, and finally it is that same bundle that will be available for release (assuming it got approved - rejection forces you back to testing so a new bundle is inevitable).