(I saw a similar ticket to this but it was resolved due to length of time.) I noticed this back in 2014 or so but it was resolved but in latest snapshot I have seen it again. The squids have a very laggy/jerky look to their animation. looks almost like a player when lagging. They glitch into blocks as well. Included video shows spawned squids as well as naturally spawning squids. video here

(Video is compressed with volumes due to slow upload speed - it made things a tiny bit faster)