This was reported to me via Fruit Servers (ty Nebula), so I tested it and was able to replicate.
In accordance to the spawning rates, a single-ability pokemon may be announced as being "HA"; IE one in50 mismagius may be announced as "HA" even though there is no second or hidden abilities available to it. Same can be said for Metapod, Alolan Raichu, Kakuna, etc.
Steps to reproduce:
1) Set HA spawning rate to 1.0.
2) Create a Spawner with whichever Pokemon that only has one available ability, such as Kakuna, Metapod, etc. Set spawning rate high.
3) Catch. Should be announced in chat via Broadcasts as being "HA".