Infinite loop at runtime

Hello,

For this program : https://github.com/OlivierSohn/hamazed/tree/repro-ghc-14521-A

The expected output is:

Before rendering animations
animation is rendered
After rendering animations

What I observe is when compiling with ghc 8.0.2 or 8.2.2, with optimizations:

Before rendering animations

I found several ways to circumvent the bug, and documented each one in the source code.

Can someone take a look? Is my program an invalid program that was not detected by the compiler?

Thank you, Olivier