I noticed while simming my PG that the buff provided by the proc of “Void Twisted Titanshard” trinket (which name is Void Shroud) is present 2 times in the detail of buff in the sim result:
The minor difference in uptime reporting is just an artifact of how some of the tracking is handled – I can try to clean that up. If you run a simulation with output level set to “Log” you’ll see that the shield and crit buff are always up for the exact same amount of time. (It is the longer of the two shown in your screenshot.)