Yes, totally normal. Keep mixing, you're almost there :).
We recommend using a handheld or standup mixer first to breakdown the butter. If you don't have one, no worries, cut the softened butter into smaller pieces and chunks. Then, using your hands, massage and work the dough until everything is fully integrated and/or looks like cookie dough.
For exact measurements, the 1/2 cup of butter should work to be 115 grams and using a large sized egg.
Here's a quick video we made to illustrate this process.