My first thought is that there must be different quality pill cutters on the market!

I've been using my pill cutter (which I inherited from my mum) for more than 2 years. My Madopar 125 tablets are double scored. I take 3 quarters of a tablet, 6 times a day. I'm yet to have a malfunction.

The brand name is Safety Shield Tablet Cutter. I just Googled it and it came up straight away. Perhaps it, or something equivalent, is also available where you live.