hbd_interest_rate fluctuates in certain conditions
I viewed that as a normal state of things, and for me it was non issue, or at least not an issue big enough to consider the change.
More on that was discussed on an OpenHive.Chat's #witness channel, I will provide more info later on, for now it's just a placeholder not to forget about the issue.
see: libraries/chain/witness_schedule.cpp there's a update_median_witness_props
It handles:
account_creation_fee
maximum_block_size
hbd_interest_rate
account_subsidy_budget
account_subsidy_decay
taking into account values that witnesses scheduled for production has signaled as their properties.
FYI: we are implicitly assuming odd number of elements, because with even it gets odd
(i.e. so our active.size()/2
works, giving us "almost median" value which we agreed that is good enough for that purpose, and avoids getting average value of two middle elements)
Please note that while such fluctuations are normal and expected and with high activity in voting (stakeholders disagree on what APR should be effective but voting in / out some of the witnesses), current issue can happen without any actions of stakeholders, just by the nature of changing witness schedule that happens roughly every minute.
Challenge here is that it operates on a witness schedule and there all the witnesses are equal, including "the 21st".
This is hardfork change