yeah, seems my grep was wrong:
root@proxmox:~# mount | grep lxc
lxcfs on /var/lib/lxcfs type fuse.lxcfs (rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other)
root@proxmox:~# pct mount 201
mounted CT 201 in '/var/lib/lxc/201/rootfs'
root@proxmox:~# mount | grep lxc
lxcfs on...