It's good to have you on board! Thanks for your comments and the bug report. We've found the bug and have fixed it on our machines. The fix will be in our next release, which hopefully won't be too far away. We just need to test Pathstorm and make sure the change is stable (it certainly appears so at this point).
In the meantime, a quick, hacky, and imperfect work-around for the bug is to start the level, bing up the in-game menu, select "Save and Leave Level" and then when back at the Challenges menu, select the "Continue Level" button. The level will load and there will be a couple exits that are buried in walls. Don't click on the buried caves unless you like hanging the game.
If you can resist that urge, you should be able to finish the level. If you can wait, the permanent solution will be out soon.
This is probably where I should issue our standard disclaimer: We'll release a new version with the fix on Cavebug.com. While we love our portal partners, we don't have control over the game on many of them and cannot guarantee that they will release the updated version. If you find yourself in this situation, the above work-around should get you past the problem.