[bobz]

Technically, quantum refers to physics at the atomic / subatomic scale, and not necessarily to the spooky effects like particle wave duality and such that we usually attribute to the term.

So, I believe this would be an "effect on the quantum level," even if it can be understood through the lens of more traditional electromagnetic physics as well.

[beambot]

Calling an electrical noise / timing bug "quantum mechanics" is hyperbole. Otherwise, every EE that touches hardware is a quantum physicist (they're not).

EDIT: Not trying to diminish the OPs impressive feat of debugging though. Hardware errors can be beastly to diagnose. When wire-wrapping an 8086 computer, I used a spool of wire with occasional (random) breaks that would intermittently open. Worst. Bugs. Ever.