VSTi Settings Not Saved With Notion File...?

So I have this solo piano project that I changed from using Notion's piano to TruePianos. I selected a non-default piano patch, and tweaked some settings in the VSTi interface, and saved the project.
Today when I open it, I'm hearing the default piano. So I open the TruePianos interface, and all the settings are back to defaults.
This would be a nightmare if it happened with one of the big multi-timbral, orchestral synths, so I gather the ability to save VSTi parameter settings applies to specifically supported orchestral synths but not to all VSTis. I this right?
I've never encountered a VST host that doesn't automatically save current VST parameter settings with the project file.
Today when I open it, I'm hearing the default piano. So I open the TruePianos interface, and all the settings are back to defaults.

This would be a nightmare if it happened with one of the big multi-timbral, orchestral synths, so I gather the ability to save VSTi parameter settings applies to specifically supported orchestral synths but not to all VSTis. I this right?
I've never encountered a VST host that doesn't automatically save current VST parameter settings with the project file.