SLX crank threads for chainring bolts

Got a 1x SLX crankset that I installed in December, which has been fine until recently I was getting a lot of creaking. Did the usual re-greasing of BB, pedal threads etc, so decided to re-grease the chainring bolts only to discover that one the thread in the crank spider has been stripped. Closer inspection of the crank-bolt showed nice round aluminium rings wrapped around it that I presume were once the threads in the crank spider.

Anyone else experienced this? Are SLX cranks that fragile? I did stick to the torque guidance of 12-14nm, but may have gone a bit beyond when initially trying to remove the creaking sound.

I'm guessing the crankset is a write-off and I need to buy a new one.