Most GoG emails are DKIM signed (it's one of the tools used by server administrators to combat spam), however, there are some that are not. (For those of you whishing to read more on DKIM visit https://en.wikipedia.org/wiki/DomainKeys_Identified_Mail to get started))

Messages that are "Free items added to your GOG.com library." are not DKIM signed and the SMTP HELO command mis-matches the sending subdomain which may flag it as spam by some systems.

Example:
A message I got after adding a game via GoG Connect came from: host-193-59-178-5.gog.com but identified itself as xen-84.atm and did not use a DKIM signature at all.

It scored 7 on my e-mail server's spam detection (fortunately it's below the threshold).


Most GoG comminications include the DKIM-Signature line which avoids the above issue.

Thanks. You might want to contact support, since they're likely to miss a post on forums.
https://support.gog.com/hc/en-us/requests/new Good thing those first 2 numbers weren't reversed or GOG's own anti-spam methods would have identified it as spam and blocked it.
hehehehehe