That's a pretty pesky bug. In all of the versions of JJ2 the "Area Warp Secret" event has been buggy, in 1.20 it stopped the regular "Area End of Level" events from working (untill you fought a boss) and in 1.23 the event doesn't deactivate upon re-entry and warps you back to the secret stage, not to mention it glitches the regular "End of Level" event untill you close JJ2. As a standard, you should only use "Area End of Level" events for the end of level, with "Secret" set to 0.

However if you *must* have a secret level, you should use the "Bonus Level Signpost" event, which acts like the "?" signs in JJ1 (which means you shoot it). The level accessed via the signpost is treated like a regular one, when you finish it, you go to the level marked in the "Next Level" field.

- JelZe GoldRabbit =:3