I'm just going to copy->paste my previous answer that helped someone else. As you already got Milo's first invite and killed Adam, you actually fulfill the conditions to get the second one I'm sure:
Prev answer:
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I went back to an old save and was able to trigger the second invite. At first it was weird cause it seemed to not be triggering, but I got it at the end. The conditions for it to trigger were:
1- Didn't accept the quest yet, but talked to Cecily and started the waiting period;
2- The waiting period was over and the green ! appeared above Cecily, but I didn't talk to her yet;
3- After the green ! appeared above Cecily I waited one night/day cycle (if 1 isn't enough for you, try several, just to test), then it appeared above the tavern/guild quest giver; ##
Edit: Here's a post where I explain the timeline of the quest as well, maybe it can help you:
https://f95zone.to/threads/lonarpg-v0-7-2-6-beta-eccma417.49993/post-9027547