The italics have a slanted double-story a, which can be accessed thru the OpenType features ss02, cv01, and salt.
If Sublime Text doesn't have support for OT features, you can make a custom version of the italics with pyftfeatfreeze which will put the alternate a's in the default slots.

@pauldhunt have you considered swapping the a's? I can see how the current setup creates legibility problems for coders. Swapping the shapes would still allow designers — who usually work with more sophisticated apps — to access both variants.

@miguelsousa Thanks for the suggestions. I don't think Sublime has support for such OT features, I will investigate using pyftfeatfreeze

Are there any plans to make the italic "a" character the same as the regular "a" without using pyftfeatfreeze?

there are no plans to update the fonts in the immediate future. i will likely explore other design solutions for differentiating ‘a’ from ‘o’ before going the route of making the italic form the same as the upright form as i personally am not a fan of the obliqued 2-story form.

Okay, thanks.

@pauldhunt thanks for having an eye on the issue.

For Windows I managed to get the a glyph with the following procedure

1. Copy the Source Code Pro Italic TTF fonts from the C:\Windows\Fonts folder to a temporary folder
2. In the temporary folder create a new folder out: mkdir out
3. Install python 3.5+
4. Install python fonttools: C:\Python36\Scripts\pip3.6.exe install fonttools
5. Copy the file pyftfeatfreeze.py to the temporary directory or some util folder
6. Convert the TTF fonts (all on 1 line):
   C:\Python36\python.exe pyftfeatfreeze.py -f 'ss02,cv01,salt' SourceCodePro-It.ttf out\SourceCodePro-It.ttf
7. Perform the same operation for all the Italic TTF font files
8. Copy all the files from the out directory to the C:\Windows\Fonts folder
9. Restart the applications

The a now has a different glyph only it is not as smooth as the other glyph. Only visible for large font size.