Velofix came by today. He tightened up the rear wheel spokes though he didn't think they were particularly loose. He was able to experience the delayed activation of PAS 3 (and 4 and 5 for that matter). He thinks it may be a problem with the PAS switch on the handlebar (which apparently works in tandem with the display unit). At this point I'm putting aside the occasional buzzing noise I hear, as he thought it could possibly be interaction between the spokes and, regardless, I could live with it if the other issue can be resolved. I've shared his report with Lectric via email. We'll see what they come back with.