After I saw that
Haiku<->Haiku eroded into silence/single emojis
AND
Opus<->Haiku eroded into silence/single emojis

I tried Sonnet3.5old<->Haiku...

Again: eroded to silence/emojis - no fight by S3.5old, and the emojis were a little more diverse than usual

Before Haiku Erosion set in, they were really interested in high dimensional mathematics, self-modeling, consciousness (and ofc quantum stuff - but more meta than quantum/ethics-y in theme)