Yes you are right, NIP-17 (which uses NIP-44 and NIP-59).
When gossip starts it does two long-lived subscriptions related to this:
INBOX: on all "READ" relays, it subscribes to all feed-displayable event kinds (including NIP-04 DMs) with 'p' tags to you.
GIFTWRAPS: on all "INBOX" and "DM relays, it subscribes to giftwraps with 'p' tags to you (which contain your NIP-17 DMs).
In both cases, it only loads one chunk, which is by default the first 35 events going back in time. Then you have to press LOAD MORE to look back further.
I don't have a guess as to what is going wrong yet. I may have to read more of my code and think about it harder.
