It's not a regular feature, and you should not have to put up with it, unfortunately this problem has also been seen in E71 as well, it's strange as some users have never seen this problem at all
I bought this phone back in Septemeber, from them have been facing the issue, had checked with Nokia Care, they just reinstall the OS and the issue was seen after that as well
Recently checked the Web and found this update, after applying this update, still faced the problem, I did a hard reset by *#7370# and after that have not faced the problem for the last 10 days, some things which I always do which I haven't, I like the clock in digital format, at present it is in the analogue formate and haven't seen the issue so far, touchwood
Do share your experiences...