KBFS breaks thunar and apt upgrade on Debian

[wom-bat]

While /keybase is mounted (the default after installing the keybase client) apt upgrade stalls at

Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.

Also thunar (the XFCE4 file manager) never opens a window.

Doing

sudo umount -f /keybase

fixes both these issues.

When running I see

$ mount | grep keybase
keybase-redirector on /keybase type fuse (ro,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other)
/etc/auto.net on /net type autofs (rw,relatime,fd=7,pgrp=73335,timeout=300,minproto=5,maxproto=5,indirect,pipe_ino=329190)
/dev/fuse on /run/user/1003/keybase/kbfs type fuse (rw,nosuid,nodev,relatime,user_id=1003,group_id=50)

I'm running Debian Unstable on x86_64, using the XFCE4 desktop environment.