maybe you have the same problem as me (and it’s not the screensaver).
In /var/log/syslog i found this messages:
Jun 13 07:12:41 raspberrypi kernel: [ 3057.339364] Out of memory: Kill process 1070 (electron) score 576 or sacrifice child Jun 13 07:12:41 raspberrypi kernel: [ 3057.339426] Killed process 1070 (electron) total-vm:673580kB, anon-rss:59472kB, file-rss:0kB, shmem-rss:214908kB Jun 13 07:12:41 raspberrypi kernel: [ 3057.373292] oom_reaper: reaped process 1070 (electron), now anon-rss:0kB, file-rss:0kB, shmem-rss:215056kB
For me it looks like electron has crashed.
After using google I’ve found a hint with other processes to change the value of vm.min_free_kbytes.
You can find it in /etc/sysctl.d/98-rpi.conf.
I’ved change the value to
vm.min_free_kbytes = 1024
After this there is no more blank screen anymore.