Pillagers captains spawning very rare in outposts

I have a raid farm in my world and after I went afk for night (8hr) , I found that the farm that previously produced about a full chest of emeralds per hour suddenly produced 9 stacks per night. according to my calculations it is mean that the outpost spawn a pillager captain once an hour. I am not sure if this is intentional or just a bug, anyway I would like if you could respond to me on this.

HOW TO REPRODUCE

1. Download this farm design: https://youtu.be/4CAsI3ZDNNI

2. go afk in pre 1.14 and after 1.14 and compare (I am not sure if this exists also in 1.14 or just in 1.14.1)

And please respond back to me if you can

Have a nice day!- efraim