I figured out that it has to do with DVCPROHD clips, when I connect 3 angles from a different camera running HDV 1080 it plays back fine, but the HVX200 footage causes the viewer to bog up.
The sequence is set for
FRAME SIZE: 960×720 HD(960×720)(16:9)
PIXEL ASPECT RATIO: HD(960×720)
FIELD DOMINANCE: NONE
EDITING TIMEBASE: 29.97
QUICKTIME VIDEO SETTINGS: DVCPROHD 720p60