In Cold Days, Ebenezer suggests that it's the emotions and conflict within humans that cause magic to behave strangely.

Ebenezar McCoy believes that the reason the magic of human wizards disrupts modern mechanics and technology—though the magic of Faeries does not—is that human beings are inherently conflicted. Magic responds to emotions and thoughts, and people's thoughts and emotions are always conflicting. This means that there is a turbulence around those with magical talent and its the turbulence, not the magic itself, that disrupts technology.

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As a result, if he's currently a changeling who has yet to decide, I'd say he would affect technology. There sounds like there is a wealth on conflict within him. That said, this is based entirely on one wizards theory in the books themselves, not on actual written rules, so this is definitely open for interpretation.

In Cold Days, Ebenezer suggests that it's the emotions and conflict within humans that cause magic to behave strangely.

Ebenezar McCoy believes that the reason the magic of human wizards disrupts modern mechanics and technology—though the magic of Faeries does not—is that human beings are inherently conflicted. Magic responds to emotions and thoughts, and people's thoughts and emotions are always conflicting. This means that there is a turbulence around those with magical talent and its the turbulence, not the magic itself, that disrupts technology.

Source

As a result, if Ebenezer is right, if he's currently a changeling who has yet to decide, I'd say he would affect technology. There sounds like there is a wealth on conflict within him. That said, this is based entirely on one wizards theory in the books themselves, not on actual written rules, so this is definitely open for interpretation.

Personally, I would probably say that regardless of the type of magic he is using, if he is conflicted / confused, he would have technical difficulties. If he's acting within a strict set of rules based on his principles, no technical difficulties.