Nary a glitch here, using v8.77 with default settings, even at the unnecessarily high 4092x1844 resolution.
Suggest that you update. For licensed users upgrades are free for up to six months from purchase date. After that, VP will continue to fully function but a fee will be required in order to register the newest. Retain your old install file and registration info.
You might also try an export at a lower-res, say 1920x1080. Let us know how it goes.