Check your .pigm, check Material Name property in the .pigm files, some of your pigm's may have same Material Name, so indigo replace materials with the same Material Name, I used about 20 external materials all works fine.

The problem is that blendigo that comes with 3.8 stable renders only particles that shown at viewport, but i have different values how many particles to show at viewport and the amount particles for render after export. It helps to manage huge amount of grass for example. Now it's broken. Exporter f...