Some glitches do go away, either over time or resetting and downloading. One such glitch is the "Name Glitch" where one letter in your Tamagotchi's name changes. Other glitches don't seem to disappear unless you get lucky, such as the dreaded "Ball Glitch" where many of your items turn into balls.
If you've been resetting and downloading lately or pausing, that may be why your Tamagotchi isn't ageing. Instead, if you want to pause your Tamagotchi, set the time to the time your Tamagotchi usually goes to bed instead (if that makes any sense). When you're ready to wake up your Tamagotchi, just set the time to the correct time instead. This will not make your Tamagotchi unhappier or hungrier, but it'll make it grow quicker.
