The Vampire got stuck in the cobra roll on two separate incidents. So they moved it to another park where the general public did not know of this.
The Vekoma incidents aren't a safety issue, so far. But now they are attempting to do more extreme stunts (the super invertigo has the vertical drop, which you are going to be 100% held up by your harness if its anything like invertigo), and the flying dutchman is one of the most extreme rides that exist currently. If there are so many simple malfunctions on their basic designed coasters, then it does not appear they are ready for the extreme designs. You have to walk before you can fly.
I just don't think their rides are fun anyhow, so to me it doesn't matter if they work, i usually skip them. Its just a shame to waste time of your day at a park hanging upside down trying to get off of a cobra roll :).