Response from LEGO SHOP
12 December 2019
Emily, Customer ServiceThanks for your review. Your set definitely shouldn't have any gaps! Those black triangles should actually be sitting further out, that way they don't make any other pieces pop off. The most likely culprit is step #66 in the instructions - if those two 1x2 plates aren't in place, the triangles will be too close in. If you need a hand troubleshooting the build, you can always get in touch at LEGO.build/Service.