Final Project: Movement blocks not working

My students are creating a tag game on their final project and have correctly used event blocks to move their hero character. However, they have added a looping block with several movement blocks to make the opposition character move about the screen but all movement blocks are skipped when they press run. Is there a problem with what they are doing or is this a problem with the application?

Without having access to the project in order to view the code, I cannot diagnose the problem. If you could provide an access link so I could help further, that would be useful to getting an answer to this problem. Thanks!