It does appear that some transactional activity might be related to the overall daily BBR tx volume to mixing level of coins ratio, as
transactions per CZ " can be marked as forced to be spent with minimum n-mixins - and this GRANTS that you will not loose unlinkability of your transaction, if you used this kind of forced outs in mixins"
So if daily BBR tx volume is low, and there needs to be forced mixins based on user choice, then it seems that generation of that random data would result in random tx also - is that what we are seeing?
I am not sure if I understood what you mean but just to clarify. Cryptonotes don't need concurrent transactions to mix with. They use all the compatible outputs already in the blockchain. This means every output with the same denomination, except for monero when RingCT kicks in.
So, (if i read your question correctly) that the answer to your question is That's not what you are seeing...
Ok. Then this is pseudo random data related to the 2 step hash? Or some bot liking 8.999 BBR?
What two step hash? Are you talking about the POW algo?
I just looks like someone has set up a 9 BBR withdrawal threshold.