You have to have an initial instance in the layout because this is where it takes the properties from. IID identifies the object instance, and the version of the Particle object with the lowest IID will be the one where the settings are taken from. It is possible that you have edited an instance of the Particle object that is not the first object of its type, it is taking the default settings from the first Particle you placed. You could create 100 Particle objects with different properties and on Create Particle object it would still use the settings of the first instance you added to the layout. Select the Particle objects in debug preview and look at the IID in the object properties, you will be looking on the left for Particles #0. The instance with the lowest IID will have the same properties as the one 'created'.
Any of the Particle objects you place in view initially will always look correct as they can have separate settings, it is only when you use the Create Object action that it picks the settings from the lowest instance (unless you specify with conditions in the event sheet).