When I apply "umount -a" and next "mount -a", I lose all cgroup mounts, and snap's stop working

here, its the difference between before and after applying umount/mount -a.:
mount|grep sys > before
umount -a && mount -a
mount|grep sys > after
kompare after before

snap list
Name Version Rev Tracking Publisher Notes
bitwarden 23 stable bitwarden✓ broken
chromium 1043 candidate/… canonical✓ broken
chromium-ffmpeg 15 stable canonical✓ broken
core 16-2.43.3 8689 stable canonical✓ core
core18 1668 stable canonical✓ broken
drive 22 stable fireeye broken
gnome-3-28-1804 116 stable canonical✓ broken
gtk-common-themes 1440 stable canonical✓ broken
hello-world 29 stable canonical✓ devmode,broken
john-the-ripper 297 stable claudioandre-br broken
kde-frameworks-5-core18 32 stable kde✓ broken
kde-frameworks-5-qt-5-14-core18 3 stable kde✓ broken
okular 90 stable kde✓ broken
opera 67 stable opera-software✓ broken