Directory /var/lib/tor/stats cannot be read

Jul 03 14:23:10.000 [warn] Directory /var/lib/tor/stats cannot be read: Permission denied
Jul 03 14:23:10.000 [warn] Unable to create stats/ directory!

I get these once a second on tor26.

I have sandboxing enabled, and systemd's limiting. No apparmor, though.

There is nothing obviously wrong with the file permissions.

AFAICT, tor does not try anything before printing this error:

epoll_wait(3, {{EPOLLIN, {u32=2977, u64=2977}}}, 4096, 8) = 1
read(2977, "", 5)                       = 0
close(2977)                             = 0
epoll_ctl(3, EPOLL_CTL_DEL, 2977, 7ffe878b2cd0) = -1 EBADF (Bad file descriptor)
epoll_wait(3, {}, 4096, 7)              = 0
write(42, "Jul 03 14:20:33.000 [warn] Directory /var/lib/tor/stats cannot be read: Permission denied\n", 90) = 90
write(42, "Jul 03 14:20:33.000 [warn] Unable to create stats/ directory!\n", 62) = 62