After some more research, I suspected that the infamous dangling variant bug was to blame. It turns out that I was right. Here's how I got my release builds to work:
I downloaded the godot 3.2.3 source, and then modified the .cpp and .h files such that the dangling variant fix would apply to release builds too. Luckily, all of this can be done by simply removing preprocessor commands. Then, I rebuilt godot and the applicable build templates. It's a lot of work, but it works.
On a side note, it's a bit too late for this but I think the dangling variant fix should apply to release builds as well. I would imagine that the vast majority of godot users are like me, and would gladly take the performance hit in exchange for not having segfaults in release builds. For those who care enough about performance that they are willing to tiptoe around segfaults, a separate build/source should be provided. But that's just my two cents...