Oh I see, you are using a render texture for the source texture and getting alpha fringing. And since it’s a render texture, you can’t use the workaround of extruding the edge colour.
Don’t have good answer off the top of my head beyond multiple renders onto the source texture with small offsets to create a bigger ‘edge’
Maybe the PlayCanvas team has better ideas (@mvaligursky ?)
This type of issue right? PNG white outline and weird edges