Difficulty
Re-targets every 250 blocks: 250 blocks until re-target insures accurate difficulty adjustments while almost eliminating the risk of difficulty stranding.
Is this some kind of joke ? lol
Clearly you know that anyone can solo mine or pool mine with major hashrate for those 250-500 blocks and make the difficulty stick for pretty much forever for the normal everyday miners.
This difficulty adjustment is so 2013 ancient, back then network hashrates weren't strong enough to even realize this major flaw in network growth & hopping hence the continuous difficulty adjustment upgrades, e.g KGW, DGW, DGW2, DGW3, DigiShield, etc.