Processing bug?

Yes, I’m well aware of what the cause is, and have refactored half of it in my own code. Yes, its design is problematic, but it works fine in a single-threaded context. And given how much else isn’t multi-thread safe it’s not much of a hardship to treat it like that. Much rather have that than some naive and slow “fix” to make it concurrent. If it bothers you that much, put in a PR to fix it properly!

It’s not actually pertinent to this issue though.