I can confirm this on zesty (4.10.0-15.17-generic):
$ sudo snap install snapcraft-forum --edge
$ snapcraft-forum
...
mmap() failed: Permission denied
mmap() failed: Permission denied
mmap() failed: Permission denied
with the following denials:
Apr 10 09:47:42 localhost kernel: [245540.761710] audit: type=1400 audit(1491835662.097:1159): apparmor="DENIED" operation="file_mmap" profile="snap.snapcraft-forum.snapcraft-forum" name="/dev/shm/pulse-shm-3385262665" pid=4756 comm="snapcraft-forum" requested_mask="m" denied_mask="m" fsuid=1000 ouid=1000
Apr 10 09:47:43 localhost kernel: [245542.442016] audit: type=1400 audit(1491835663.777:1160): apparmor="DENIED" operation="file_mmap" profile="snap.snapcraft-forum.snapcraft-forum" name="/dev/shm/.org.chromium.Chromium.NRaA58" pid=4756 comm="Chrome_IOThread" requested_mask="m" denied_mask="m" fsuid=1000 ouid=1000
This may be related to some mediation fixes surrounding mmap. Let me talk to the apparmor devs and if needed I can propose a PR.