Someone commented in a post here that they wanted to take a bus from Prague to Nürnberg on Apr 4, but it isn't running after Apr 3. I did a few quick checks and that appears to be the case. I downloaded the Bahn brochure for the Prag to N'berg IC bus and, it lists the schedule as daily and doesn't say anything about it being cancelled or not running on certain days, BUT, when the brochure was downloading, the URL included the words "final_brochurel". I noticed that the Prague to Munich bus also was not running after Apr 3.
Is it something about Prague? Other IC bus routes (Berlin-Kopenhagen and Munich-Zürich) that I checked on the Bahn query page did show operation after Apr 3.