Does 194.42.48.120 work correctly?
Obviously not, it has a different SOA serial for the .ch TLD than the other nameservers:
tulku.nic.ar : 2008012501 rip.psg.com : 2008012501 domreg.nic.ch : 2008012501 ch1.dnsnode.net : 2008012501 dns.princeton.edu: 2008012501 sec3.apnic.net : 2008012501 merapi.switch.ch : 2008012501 ccTLD.tix.ch : 2008012300 ^^^^^^^^^^
Looks like ccTLD.tix.ch is out of sync..
cheers, - Fabian