There seems to be a big issue with outline and TMP. In both UIToolkit and UGUI when using TMP, the outline doesn’t properly render. This has seemed to be an issue for a long time from other posts? (or maybe it is recent?)
The top “Hello” is TMP in UGUI and the bottom is unity’s standard text. I didn’t add UIToolkit, but its the same issue as the top.
The above behavior is simply the result of using either SDFAA or SDFAA Hinted as Atlas Render Modes in the generation setting of the font asset.
To understand the difference between these SDF sampling modes, please see the following post / thread .
P.S. There is an issue with the SDFAA sampling modes which I plan on addressing at some point. However, as per the post I linked above, this sampling issue is only visible on text with an outline that is displayed at 72 point size or larger. Now given these text objects are them more likely to be titles which tend to be more heavily styled, I recommended using a static font asset using the SDF16 sampling mode.