It’s really hard to tell since you put such small images here to view, and you didn’t tell us much about your setup.
However, I’m going to echo what Dave said, because what I’m seeing above is not an anti-aliasing issue, it looks like ringing in a codec that is compressing too hard or is dealing with channel clipping, or has too low a color resolution.
Here is the information we need to help you diagnose this:
1) Your project WORKING SPACE. what working colorspace (icc profile) is set, what is your bit depth, and are you linearizing?
2) What version AE are you on?
3) As Steve asked, are these text layers inside AE, or are they illustrator? Photoshop?
4) What filters or adjustments are you adding? Motion?
5) How is your output module set for color management? What codec are you going out to and what are teh codec settings (bit depth, compression amount, etc etc.)
If you tell us THESE things, we can better help you solve your issue.
GENERAL THOUGHTS:
1) After Effects does not have a “problem with red”. However some codecs certainly do. NTSC was notorious at mangling red in the image, so much so that even today when they cast cars for a TV show they say “NO RED”!!
2) Sharpening filters can cause the kind of artifact you are seeing. But also so can using a bit-mapped image file (i.e. png, jpg, etc) at too low a resolution. Since you have a “before” image at very low resolution, let me ask: is that the actual image you put into AE for the text?
3) If you are not using the built in text layers, you still want to stay with a vector type file (ai, svg, eps) and NOT a bitmapped image. Then, set the layer to “continuously rasterize” — it’s the little layer button that looks like a gear.
4) Also, while I do normally recommend working in linear light, in every version of AE I have used, linear mode messes up the built-in antialiasing, and you need to do a lot of manual tweaking. So if you aren’t compositing and just doing flat text, sometimes 16 bit gamma encoded is best (ESPECIALLY if you are outputting alpha channels).
5) Some codecs, like Avid’s, really do badly on things like text. But also too heavy compression (too low a profile) can lead to these kinds of artifacts in many codecs, particularly DCT with low resolution color sampling.
On this last point, this *looks* a lot like the kind of artifact you get with aDV codec. Part of the reason is the color is subsampled at a FOURTH of the resolution of the luminance. And remember that the majority of luminance is in the GREEN channel (70% or more). Red typically makes up about 18-22%, and blue less than 12%. So while a pure green hard edged object like text might make it through the codec okay, red or blue might get stepped on.
If you *are* fighting the DV codec, then I suggest either desaturating the colors, or mixing in another color so that you are not just primary red, green, blue. For instance, I would not be surprised if you added in some green to make it more orange, instead of red if the problem suddenly disappeared.
Best of luck
Andy
Andrew Somers
VFX & Title Supervisor
https://GeneralTitles.com