Possible fix:
Delete the cache: ~/.config/skypeforlinux/Cache/
Skype start command: nice -n 19 rm -r ~/.config/skypeforlinux/Cache/* ; nice -n 19 /usr/bin/skypeforlinux %U skypeforlinux --disable-accelerated-video-decode=true
Skype start command vanilla: /usr/bin/skypeforlinux %U