Same problem on Ubuntu 18.04. Xscreen ignores Caffeine
caffeine --version caffeine 2.9.7 xscreensaver -v xscreensaver 5.36, copyright (c) 1991-2016 by Jamie Zawinski <email address hidden>. xscreensaver: 17:53:52: running as xscreensaver: 17:53:52: in process 14560. xscreensaver: 17:53:52: already running on display :0 (window 0x1e00006) from process 3250
Same problem on Ubuntu 18.04. Xscreen ignores Caffeine
caffeine --version
caffeine 2.9.7
xscreensaver -v
xscreensaver 5.36, copyright (c) 1991-2016 by Jamie Zawinski <email address hidden>.
xscreensaver: 17:53:52: running as
xscreensaver: 17:53:52: in process 14560.
xscreensaver: 17:53:52: already running on display :0 (window 0x1e00006)
from process 3250