This has never happened before but when I export a single frame from Photoshop as either a PSD or PNG it displays different colors when I open it in Photoshop. Both aftereffects and Photoshop are aligned to the same color profiles.
Working on a Mac/High Sierra with the latest versions of both after affects and Photoshop
This may have to do with how AE sees/works with color in 15.1
When the project working pace is set to None, the new Assume Working Gamma control allows you to select whether to use a gamma value of 2.4 (Rec. 709) or 2.2 (sRGB) when converting to or from linear light.
Assume Working Gamma defaults to 2.4 (Rec. 709) for new projects. This is the recommended value unless you want to emulate the behavior of After Effects 14.2.1 and earlier releases. Projects last saved in After Effects 14.2.1 or earlier releases are set to 2.2 (sRGB).