Yet the picture does not reveal the noise one of those cranks was emitting during Kristiansand #1 ... which i’m sure is all resolved now.
It is
The splines in the left crank arm had worn out, resulting in play on the axle.
Excellent customer service from Quarq USA, although the crankset was already out of warranty they sent me a pair of "blemished" crank arms (sans spider obviously) even paying for shipping. Blemished meaning there's a small dull spot in the paint on de inside of one of the cranks.
For good measure I also put in a new bottom bracket. It's all good now and since I no longer have a reason to swap the cranks between bike I'm confident it'll stay put.
