Alright, @valgur, seems like the narrow BurstIndex range on TOPSAR-Split was the actual problem. When I set <lastBurstIndex>36</lastBurstIndex>instead, I get the full data.
How do I know, programmatically, what lastBurstIndex should be? I am running the same graph via gpt with varying numbers of inputs. Can I just set it to some large number, like