Strangely enough my Panasonic box did this for a few days, but is OK again now. You could try unplugging the box, waiting for a minute or so and then replugging and switching back on. The box will scan for channels again and it may solve the problem.
PS. What is your receiver model and what version of software are you running?
Sky HD, TM6800HD, Manhattan Plaza ST550 and TM1500 CI+. 1.0m dish and 36v motor, Panasonic DVD HDD recorder and Panasonic video/DVD recorder. Sony G800 HD TV stand/surround system + Sony KDL40W2000. Infinity USB, Elvis, CAS1, CAS2.
I know this might sound silly but I suppose in 'picture settings' the search and scan banner timeout is not set to zero seconds. It is poss to set it to that, in which case the channel info will not appear on the screen when changing channels.