Oh, Sometimes that happens unintentionally... I once rewired a place where two DIYers (a lawyer and a medical doctor) had rewired the bathroom, adding a second panel and a new circuit (the old panel was full and hadd odd old breakers without a DIN rail). They used 2.5mm2 stranded wire for all their work and the bathroom circuit (think 3kW washing machine) had two(!) strands actually under the screw of the breaker, all others had been squeezed out or snapped off. I tried to redo the connections using ferrules but gave in and pulled new wires since the stranded conductors + sleeved ferrules just took up too much space in the boxes.
We also replaced both panels with one large new panel, the old breakers were the Austrian FPE equivalent - NoTrip solid link
