last_sent_seqno > end_seqno can be sent when items are deduped

Created 3 items with same key (diff values) and let them persist to disk.
Then requested the first 2 mutations. However, I only get the 3rd mutation, as seen in upr stats:

eq_uprq:mystream:stream_0_end_seqno: 2
eq_uprq:mystream:stream_0_flags: 0
eq_uprq:mystream:stream_0_high_seqno: 0
eq_uprq:mystream:stream_0_items_ready: false
eq_uprq:mystream:stream_0_last_sent_seqno: 3
eq_uprq:mystream:stream_0_memory: 1
eq_uprq:mystream:stream_0_opaque: 469762303
eq_uprq:mystream:stream_0_start_seqno: 1

Not sure what to expect here. The protocol spec notes that we send up to end_seqno and maybe STREAM_END could be sent.

I'm also wondering if there're any implications to not being able roll back to some older mutation.