After upgrading to 13.0.6snap1 custom theming doesn't work

After upgrading to 13.0.6snap1 chaniging theme to custom logo, colour and background isn’t working. Tried disabling/enabling snap, but theme remains default. I also did snap revoke nextcloud to revert to 13.0.5snap1, but Theming still doesn’t work (as it used to). No obvious traces in the log.

Snap is installed within Ubuntu 14.04 x86_64, but it shouldn’t matter.

Any workaround?