I'm using a macbook pro early 2015 13inch 512gb 8GM RAM Since i installed 10.12.4 i have graphical glitches when i'm connected to an external display in clam shell mode. The glitches are like horizontal lines appearing and disappearing on the external display. I don't think it is hardware based, since before 10.12.4 I never had this problem even not on El Capitan. The glitches are not appearing on the display of the macbook itself but only on the external display, which worked fine before 10.12.4. I already tried NVRAM reset and SMC reset but this does not resolved the issue. Anyone having the same issue?