I cannot preview a loop and merge block

Hello everyone,
I am implementing a loop and merge block in my survey but there seems to be a bug. Every time I click on "View block..." from the top right corner, it never shows me the preview of the loop and merge block. It only display the slider question that should go with each of the fields of the loop and merge.
Surprisingly, the loop and merge block DOES work when I hit Preview survey. But i don't want to resort to that because that just starts the entire survey from the beginning. I only want to test the loop and merge block.
Additionally, I often cannot add a piped text as the question text of my multiple choice question. It click on piped text and select Loop & Merge fields but nothing happens. I have to click out of the survey and click on it again, go the question and try again. Sometimes it fails again, sometimes it works.
Am I doing something wrong? Is there a bug with Qualtrics? Thank you