corrupted ellipses in SVG files

[12Me21]

I've noticed that several emojis have differences between their PNG and SVG versions
for example, the beak in chicken:

other examples

bat (head/neck shape)

loudly crying face (inside of mouth)

fountain (the water at the bottom)

eye in speech bubble

skull (eyes)

A few more which aren't as easily visible:
- honey pot
- sake
- woman's hat

from what i can tell: this happened when the SVG files were optimized (starting around release 2.5.0),

original shape	ellipse

From what i can tell:

• Originally, the emojis were edited in Adobe Illustrator, and saved as .ai files. (This is a proprietary format, but it stores shapes in roughly the same format as SVG and can be converted losslessly).
• The SVG and PNG versions were generated automatically from these .AI files.
• Starting with v2.5.0, the SVG files were optimized, replacing some <path> elements with <ellipse> (and <circle>) elements. (among other changes)
• The way it detected ellipses wasn't strict enough, and some shapes were mistakenly turned into ellipses.
• At some point around v12.0, twemoji switched to using the SVGs as sources, and removed the now-redundant adobe illustrator files.

So: the current SVG files still contain those optimization mistakes
To fix this, all SVGs (except the ones from after v12.0) should be regenerated from the most recent .AI files, but with safer optimization settings (or perhaps the same settings, if the ellipse bug has already been fixed)
(here's the last commit before the AI files were removed: https://github.com/twitter/twemoji/blob/7f9de7ceb8962c1b505486e23dee24282385b28b/assets/)

[12Me21]

Perhaps the best example i've found so far is:

somehow, just one of the eyes was replaced with a circle

[elephantpanda]

The optimisation has made turned them into "cal-arts" style 😔

[12Me21]

I've even found what appears to be one from v13.0.0:

There's no correct version to compare it to, but i'm fairly certain that at least one of the ellipses at the top of the pot are wrong (perhaps more)

[elephantpanda]

Not sure what the point of optimising the shapes to be ellipses is? You at most save a few characters from the SVG file.