For me this happened after completing the survival quest. I solved this by jumping over the gate of Abeyance dungeon (possible with some bow action and climbing), completed the dungeon and went to the next world. He spawned there right after entering it and I could hand in my survival quest, get the next one and basically ran through Abeyance dungeon again, killing Jabberwock a second time. Maybe something similar can help you too.
For me this happened after completing the survival quest. I solved this by jumping over the gate of Abeyance dungeon (possible with some bow action and climbing), completed the dungeon and went to the next world. He spawned there right after entering it and I could hand in my survival quest, get the next one and basically ran through Abeyance dungeon again, killing Jabberwock a second time. Maybe something similar can help you too.