Its both the engine changes fault that it crashes and not the engines fault that it crashes.
Godot works fine in tons of games, the thing is porting a game after years of development to a new engine will always be a nightmare. That goes double if you have a small team. And again double if you are crowdfunded and expected to create a running build regularly. And it goes even more double if you port it from a highly specialized engine like renpy to a very broad engine like godot.
Before the dev had the functionality of renpy to work with, which doesn't allow a huge amount of creativity in how things work, but they did work. The functions were thoroughly tested and stable.
Now they need to implemented everything on their own in godot. What a small dev team makes on their own in a couple months is just not gonna be as stable as something that's been designed and tested over years by a dedicated team and there's gonna be a ton of bugs if you do it. Like we see here.
Let's hope they manage to fix most of these bugs and get more comfortable with the engine as time goes on.