All the users are seeing clarity problems when logging into PAM from their MACs running the High Sierra version of OS X(10.13). The users logging in with the Windows PAM client see no such problem.
Searching through some Mac/OSX forums some threads were found regarding changes in OSX High Sierra and Mojave about "font smoothing". There were lots of complaints from OSX users regarding the distorted text issue in many apps. While earlier versions of OSX had an option in the OS settings to turn this font smoothing feature off, in the last two versions of OSX, High Sierra(10.13) and Mojave(10.14), the feature is still "on" even when set to off in the GUI.
The most recent versions of OS X, 0.13(High Sierra), and 10.14(Mojave) are not currently supported by PAM. Testing of Mojave is to be done for PAM 3.3, but in the meantime a solution was needed for this issue.
Though the High Sierra and Mojave versions of Mac/OSX are not yet supported by PAM a solution was identified in the Mac/OSX forums. To turn this feature off, do the following:
1. Open OSX terminal
2. Type defaults write -g CGFontRenderingFontSmoothingDisabled -bool FALSE
3. Logoff and back on (or reboot)
This resolved the text clarity problem. For those who don't want the change made permanently it is possible to enter the command again, changing FALSE to TRUE. You may toggle the feature as needed.
Note that High Sierra and Mojave are scheduled to be supported with PAM 3.3.