Thx, that fixed it for my machine with the Nvidia GPU. As for the other machine with the AMD GPU, I found this solution from a different post to work:
Edit: Later found out the change in VLC Preferences listed in solution above can cause flickering black screens on other file containers, codecs; I found this other workaround for my machine with an AMD GPU:
Preferences > Input / Codecs > Next to Hardware-accelerated decoding, select VDPAU video decoder instead of automatic in the dropdown box