I’m not really sure. If your green square is the same as my green square (and I’m not sure if it is, because your green square within the emoji picker shows a border around it when you’re picking it, and my green square never has any borders around it — even when I’m picking it), maybe it’s possible that Airtable can’t render these progress bars properly on Windows? You may want to reach out to email@example.com to ask them about this. Ultimately, it would be awesome if Airtable just natively created a progress bar field.
What you're looking at is sadly how emoji's work on the internet. Typing in a text box uses whatever emoji font is default for the browser you're using, while what it looks like after you submit the text is based on whatever emoji font the website uses (the website does not have to but can use a different emoji font from the browser).
This means Airtable just uses whatever emoji font you're computer is using, while community.airtable uses it's own, different emoji font.