Steps to reproduce:

1. Open attached project (or a new one, makes no difference)
2. Open profiler, and run empty scene
3. Check the 'Memory' tab, specifically, the 'Total GC Allocated' graph, notice the GC memory is released every 100 frames or so (the red graph drops)
4. Build the project for iOS or tvOS
5. Run the same scene again
6. Check the profiler's Memory tab again, notice that this time, 'Total GC Allocated' is being released way less frequently (on my machine, every 3000-3500 frames)

Workaround: Placing a simple script, that calls GC.Collect() once every 100 frames makes the issue disappear.