Hello pijujica
You have found a nice example.
But I don't believe that it is the result comming from a Bot. It may simply come from the following situation :
When everybody is buying a resource it can hapen -I've seen it many times- that all little piece of stone/iron/wood is sold. And during a small time no offer exist. During this time, prices are free without any control, and every players can decide either to sell at very high price, either to sell at very low price.
If IO really wants to master the prices (I am just a player) I believe that a simple additionnal test can be added in the rules.
When no offer is on the market, any new offer should be tested towards the mean value of the previous day - you know this value is given on the graphic showing the day by day prices.
In that case all selling prices will be bound to the rule that says that no offer can be given if its value is exeeding 2 times the market price.
Have fun !
And if IO wants to implment this test , that kind of variation will simply disapear