It's not weird. Plenty of people have not had problems with aluminum wiring in their houses, even when screwed to copper fixtures. Others have had house fires.

The lack of a 100% instantaneous failure rate does not mean there was a good engineering design, or even any engineering design past appearance.

In the case of magsafe, the incidence and number of claims of fraying, actual wire melting, etc, was so high that it was very clearly "bad engineering". (You are talking about at least tens of thousands of adapters that were actually replaced after actual signs of failure)

The case was settled through ADR 6 months after ADR starterd, and included apple agreeing to replace all adapters that showed any signs of strain relief failure for up to three years from the date of the initial settlement.