It appears that FlightConnections' information is out of date. The only carrier they list operating flights from CMB-ZRH is Edelweiss Air, a vacation-oriented carrier based in Zurich. Currently Edelweiss Air will sell you a flight from CMB–ZRH or vice versa in March or April 2021 (or in winter '21-'22, which lends credence to your suspicion that these flights are announced long in advance.)
Edelweiss's cancelled flights page notes that their flights between CMB and ZRH have been cancelled between the dates of October 31, 2020 and March 12, 2021. However, the Internet Archive version of the same page from December 20201 shows that the CMB–ZRH flights were only cancelled until January 31, 2021 at that time. It seems likely that when Edelweiss made the previous announcement, they were hoping that demand might recover by the end of January; but now they don't think that it will until March at the earliest. (And to be honest, this also makes me skeptical that they will operate the flights they've scheduled in March or April.)
1 I had to go poking around in the source code of the Internet Archive page linked above to extract the dates of cancellation. Whatever CSS mojo that displays or collapses the sections of the table doesn't work properly via the Internet Archive version, but the information is still in the source code.