Did you turn your particles off? That might be your issue.
I ran the command and all I got was [{}, {}]
The command I summoned him with was /summon pillager ~ ~1 ~ {PersistenceRequired:1,Silent:1}
Note: I summoned him as a silent, persistent pillager so he wouldn't despawn. I did summon him with his crossbow, however.
Nicholas Bartos
Did you turn your particles off? That might be your issue.