Arfa Daily wrote:

In many years of repairing this stuff, and replacing electrolytics that have
failed any way from passively to explosively, I have only ever found three
things which cause their demise in the way you have described.

1) Excess voltage across them
2) Incorrect polarity of voltage across them
3) Excess current through them

3) is obviously the most difficult to diagnose, as it really requires a
'scope to see what's going on.

An HF fault causing high local ripple ?

Graham