I have actually had a couple play up but. I considered that more to do with placement and design. Where you can get into strife is when there is around six in a tin can. My normal fix for that carry on, is a lump of brass, corrugated. earthed & them separated by it.

I do Tag & Test & the stuff I have was suited to it. I see no gain from insulating the transformer, If its got earth leakage above a certain point and you have RCD's it won't stay in circuit long. If I suspect a transformer, I will isolate the windings & not just check them for leakage to ground but leakage one winding to another. I have had fixable shorts inside the bells. Do watch out for "shielded" transformers. They by way of design, will place a charge on a non earthed chassis.

Often the kink is related to mechanical stress. I always kink new wire on a top cap repair, and I have seen a few stress failures in hard jacket caps due to mechanical stress on the leads.

My RDH & I think there is more than one here, as well as other different publications Quotes 3rd edition 10th Impression 1944. I started fiddling with radio's in 1963.

I have never had a problem either with the orientation of replacement modern capacitors.
But we were talking about poor layout or chosen value perhaps causing instability.
I guess it’s then only academic, or OCD, but would suggest to keep an eye on some components used for example in high frequency transmitters, and high gain power amplifiers.
JJ

When you repair a lot of radios over a along period, to the point where you actually carry an inventory of capacitors, resistors & pots etc. There was a period around 2000 where in two years, over 150 sets principally chassis only repair, crossed the bench.

The range of faults an the hacking was incredible.