Crafty, the name of things in the game may have created a prioritization mechanism that determined which enterprise of a player received the glitch (i.e. first or second alphabetically has the glitch). The name Simple Blue II was prior alphabetically than Space Inc, and Unkempt was later alphabetically. Personally, I believe that for players affected by the glitch, it may affect their oldest enterprise in terms of continuous ownership by a player (I believe that the enterprise sold by CP was owned by him longer than Space Inc so the sale could have move up the error) or oldest enterprise is terms of lowest ID number (22145 is lower than 21362, the ID number of Space Inc... and my account is not affected by the glitch).
(Of course, this is all speculation until it is proved.)
The problem with testing out the bug is that not all players appear to be affected by it (I don't believe that my account is affected by it), but players that are possibly affected by it that own 2 enterprises appear to have 1/2 enterprises enterprises on a world affected. If it could be identified how the enterprise affected is determined, it could at least be controlled in absence of GM action.
This looks like the last month of that spike showing on the graphs... like Laguna pointed out, the change is indicative of a glitch as it created a permanent impact and raw materials costs are also not know for large spikes, but smoother fluctuations in price because.