Game skips at specific points in level (not garbage collector)

Hi, I'm working on a side scrolling 3d platform game for iOS.

It normally runs at a decent speed / frame rate however there is a couple places in the game that when you get past it on the device the screen freezes for a moment (around half a second) and then play resumes as normal. You can then go back and forward over the same point in the game and it won't skip. If you reload the exact same level you're on, it won't skip again when you pass the same points you passed last time but if you load a different scene and then come back to this scene then it starts skipping again. This only happens on the device, not the computer when testing it.

I don't think it's a new texture being loaded because there are no new textures or models that can be seen when the camera follows the character past that point in the game.

I also don't think it's the garbage collector (although it is a very similar skipping effect) because it happens at a certain place in the level and only once during the whole level.

Also there are no spikes in the Unity profiler when playing on the computer with the remote or just by moving the character through code, as I said earlier, there is no noticeable slow down or anything when playing it in unity on the computer. However there is a jump in the Xcode internal profiler when running it on the device. At the same time these slowdows occur, there is also a spike in the "cpu-ogles-drv" max number.  Usually it is around 5-8 whereas during the slowdown it increases to around 85 - maybe that can help suggest what might be going on?

Anyway, thanks for any help you can give - I really appreciate it!

Unity forums thread; ://forum.unity3d.com/threads/110655-Game-skips-at-specific-points-in-level-(not-garbage-collector)?p=734080#post734080