After upgrading from Jenkins LTS 2.46.1 to Jenkins LTS 2.46.2, the colorblind support seems to be broken.
Before the upgrade, our users with colorblind support enabled were correctly getting the "S" and "F" overlays.
After the upgrade, they are no longer being shown. There was no change to the greenballs plugin, it stayed the same version.
The LTS upgrade from 2.46.1 to 2.46.2 was done because of the cross-site scripting vulnerabilities fixed between the 2 versions. I do not know, but suspect, that the breakage in the colorblind support might have been caused by the vulnerabilities being fixed, based on how these were implemented.
Details on the items resolved in 2.46.2: https://jenkins.io/security/advisory/2017-04-26/