I've had good luck with Ikea in general (typing at a desk from there, 20 years old and counting) but I've never had any wooden pegs break like that before.

I did know how to fix it - my toolbox was all of ten steps away, so once I stopped grumbling (and by 'grumbling', I actually mean cussing a blue streak at both whoever did the instruction booklet and the braindead lobcock in QC who passed the wooden pegs as being up to par) and got the drill it only took a couple minutes to get them out. And as I fortunately had bought more than one of the same, the single spare peg in each box was enough to replace the broken parts!