Using my BlockStatsExplorer, you can see that the number transactions per block with op_return >= 80 bytes increased around block height 916000, i.e. a couple of weeks at least before v30 was released, now a typical block has 20 of them
But it spiked to 60 such txs per block for periods about four or five months ago, block height ~900000. Those evil spammers must have got in a time machine to go back and use Core v30 back then. 😀
My BlockStatsExplorer is hosted here: https://satsandsports.github.io/blockstats-explorer/www/index.html



