They've been on an upwards path since SF23B was introduced, they've done well to sort out some tyre issues and enable themselves to do races like Monza 24 or Jeddah 25. Nothing gave any impression they'd mess up this bad with such a crucial design concept flaw, but it's not the worst thing that happened
The lack of commitment to sort out the most painful problem is the worst for me. It's not an easy decision for Serra to make as he came too late last year to have a full understanding of all the details of SF25 - especially since his time is split between 25 and 26 cars
I've underestimated the amount of personal vanity some former engineering leads seem to have, which is probably the worst character flaw an engineering lead could have