Mini Grand - forgetting settings

I am using Mini Grand AIR plugin with the Ardour for a long time. Recently (since about Ardour 6.5 and it persists with Ardour 6.7 and the newest version of Mini Grand) it seems that settings for the plugin are not saved, every time I open the project the volume in the plugin is set to 0 and all settings are at som non-sensical default. This did not happen with earlier versions of Ardour. Anyone knows what may be the problem?