I killed Glommer twice and did not see Krampus spawn. The server setting had Krampus set to "less", but it seems it took it as "none". Might want to look into it. (BTW, I didn't know that killing Glommer would summon him, just found out and that's why I'm reporting it here.)
Steps to Reproduce
Kill Glommer the night before a full moon on a server with the Krampus setting set to "less".
This issue has been fixed in either a future version or updated in a previous version.