I reached out to TTA regarding this focus pulsating issue. They sent me a prepaid label to send the lens back for a replacement. I received another copy and it has the same pulsating issue at aperture higher than f2. Then I realized one thing and maybe you guys have already figured this out. This pulsating issue is only there when in AF-C mode. In AF-S mode, it focuses and locks without any issue at any aperture. I will use this lens in AF-S mode for now until TTA figures out this issue.
