Ubuntu – Brave browser not starting due to snap mount namespace error

Brave installed from snap was running perfectly fine for months.
Since two days it is not starting when clicking Brave icon from launcher.
When attempting to run Brave from command line just calling brave I am getting following warnings, browser starts but without all my profile data (bookmarks, configuration, history), and it is in unsafe –no-sandbox modee.

main.go:224: cannot change mount namespace of snap "brave" according to change mount (/snap/gtk-common-themes/818/share/icons/Suru /snap/brave/44/data-dir/icons/Suru none bind,ro 0 0): cannot use "/snap/gtk-common-themes/818/share/icons/Suru" as bind-mount source: not a directory
Gtk-Message: Failed to load module "canberra-gtk-module"
Gtk-Message: Failed to load module "canberra-gtk-module"
Gkr-Message: secret service operation failed: An AppArmor policy prevents this sender from sending this message to this recipient;

It looks like snap-AppArmor integration issue.

Ubuntu 18.04.1 LTS.

snap version

snap    2.36.2
snapd   2.36.2
series  16
ubuntu  18.04
kernel  4.15.0-42-generic

apt policy apparmor

apparmor:
  Installed: 2.12-4ubuntu5.1

snap info brave

name:      brave
summary:   A browser with your interests at heart.
publisher: Brave Software (brave*)
contact:   https://community.brave.com/
license:   unset
description: |
  Browse faster by blocking ads and trackers that violate your privacy and
  cost you time and money.
commands:
  - brave
snap-id:      uE3hSmGE91m9MpbDEnUWi2vpeumH6gmv
tracking:     stable
refresh-date: today at 10:26 IST
channels:                              
  stable:    v0.56.12-5.dev (44) 160MB -
  candidate: ^                         
  beta:      ^                         
  edge:      ^                         
installed:   v0.56.12-5.dev (44) 160MB -