During the first 3 seasons Simpsons was animated by KlaskyCsupo, “animation executive producer” and “supervising animation director” was Gábor Csupó. After he left animation style changed to more conventional.
So while the characters, writing and plotlines were not as genial as in the following seasons the animation style was much more interesting, with strange perspectives and point of views, distorted spaces, etc. Just look at this early recording: https://www.youtube.com/watch?v=2LUf-GGHpuU
Here is a compilation: https://www.youtube.com/watch?v=2gPay3RUp1c
I never noticed this, it just looks like this for a few frames, but yeah, it’s a strange design choice, it makes the characters look like they are made from clay or rubber.