How have you tracked the block_reward?
Polling from WTM every 15 min 
Chart is for mining reward, but it depends only on diff and block reward, diff is changing smoothly, so there should be no such jumps.P.S. Dark mode is scary
Navbar is still white. Also try to reduce contrast between elements.So the green line is the reward mined with a certain hashrate?
For me looks to mimic the difficulty swings perfectly.
Thought you have plotted the block_reward as listed per block.