Matteo - for your first problem, that shouldn't be happening. We only load the JS for the user's targeted variation and remove it if it changes for whatever reason. Can you provide more information about what you're experiencing or some screenshots? For the second problem, we are working on implementing a quick way to view and remove visual changes from a variation on the Experiment page. This should allow you to remove yourself from the impossible situation you're in. If you plan to keep the redirect, I would suggest creating another page on the Experiment page and pointing the Visual Editor to the page being redirected to. There you should be able to make visual changes to the page after the redirect.

Hi Matteo, regarding your 2nd problem, I've filed a bug here: https://github.com/growthbook/growthbook/issues/1393 and we have a solution in review, here: https://github.com/growthbook/growthbook/pull/1394