Not sure this is really a bug in Halo 5’s theater mode, but I thought it was something somewhat fun worth pointing out.
When something gets destroyed while running a recorded game (vehicles, mostly) the debris they leave behind stays until it’s cleaned up on its own after a set time. However, if you go back on a clip where a vehicle gets destroyed after watching it blow up once, the state of the vehicle is brought back to what it was prior to getting destroyed, but whatever it left behind from its previous “death” stays. That means if you keep looping a clip where something blows up back and forth, the debris that vehicle keeps piling up more and more until you stop. Essentially, you’re making a mess of that vehicle.
Here’s a good example. The Prophet’s wrath on Apex 7 leaves a lot of junk when it blows up. The stuff looks like big, purple space chips!