Hi, I've discovered a bug. Every time I play the game, it resets the text speed. I set it to instant, play the game, save and come back and it's back to half. Love the game, btw, I've been playing since the 0.17 release.
That issue seems to be real, I play on Ubuntu Linux and same thing happens.
It may be a RenPy bug, though. There is this issue already reported: https://github.com/renpy/renpy/issues/3047