When I added melted er to ice cream ingredients, why did the er form tiny globules, curdle?

I made a er pecan ice cream, melted the er and browned the pecans. I added it to the cream mixture when I thought it was cool enough. The er seemed to curdle or form tiny globules. The icecream is great but has small ery curds throughout. Was the butter too warm to add to the cold cream and milk mixture? I want to make it again, but want it to be smooth.