As a more detailed follow up question to my earlier one ( Which types of firearms would be damaged or broken by a global change in combustion intensity? )
There is new magic entering the world(approximately present day tech level or higher) that allows for a number of fantasy-like spells to be cast. This magic works by a person using their "Life energy" to pierce a dimensional barrier, and draw energy from a parallel "Magic" Dimension to cast a spell. As the barriers between dimensions are pierced more often, background magic energy dissipates into our dimension.
One of the side effects of this background magic energy is that it disrupts detailed electronics as well as some types of combustibles and explosives. Computers, firearms, and many types of advanced technology no longer work properly. Living entities are not impacted by these effects because their "Life energy" passively nullifies the reality altering side effects of magic background energy. The effect is localized to the areas where magic is used often. The effects are subtle enough that they don't disrupt large scale geological activities.
With all of the background details taken care of, the actual question: What would be a way for this to be explained without too much abuse of logic or scientific law? What specific changes would this magic background radiation need to alter to get the desired effects of nullified technology, with the smallest number of other side effects?
I'd like to have a better explanation for these side effects than just saying 'Because magic'.