If Resonate Stems aren't dropping or allowing him to combine them, then he most likely also has the Nascent Dawn quest that's asking him to open a specific Sleeper Node. This quest will prevent you from obtaining or combining Resonate Stems until you finish it, and you don't need Stems to open the Nodes for this quest.
English
-
Both he and I have completed Nascent Dawn and have Polaris Lance. I dont know what the issue is. i got some resonant stems drop from a heroic event the other day but it was a one off thing
-
It's character-based, so if the particular character you're using hasn't completed that step of Nascent Dawn, Stems won't drop or combine on that character until finished. Note that abandoning the quest doesn't work.