Happened to me in snapshot 18w50a after taming a parrot.
Unable to replicate right now but I experienced this in 18w48b when first running the snapshot (using the command to locate new villages). The only way to replicate would be to try it first thing when a new snapshot releases.
I also experienced this bug in snapshot 18w47b, but only in one village and I could not reproduce it so I did not report it.
[media]@Asteraoth, the world was created in snapshot 18w43b but updated to versions 18w44a and then 18w47b. I ran into the problems with the /locate command when attempting to use it in snapshot 18w47b.
I have run into this same problem while first running the game in snapshot 18w47b (which I assume is the same version you're using as you're looking for pillager outposts) and it will resolve if you just wait a some time after loading your world.
note: to replicate this, you may have to switch in and out of versions and create a new world. I can't replicate it because I've been playing in the snapshot for awhile.
Unable to reproduce in snapshot 19w02a after using the command to locate a mansion and pillager outpost. There was quite some lag, though, which I expect was just a result of loading up the world in the snapshot for the first time.