Instruments not loading in Halion 3

This happens sometimes in my projects - an instance of Halion suddenly doesn’t play and when I open it, I find that the instrument is selected in Halion but has unloaded itself from the patch. I attached an image as an example - in this project the sound called Sailor’s Dream usually plays but today when I opened it, it has unloaded itself and double-clicking it does nothing. It won’t load. What is the issue here?

Same here. Good to see that Steinberg is on top of it. /s