I would suspect you have a failing keypad.
Is it possible that some
spray cleaner accidentally got into the controls?
Direct spraying of
cleaners on the keypad and steam from the
cooktop can damage the controls.
I always recommend that you spray non-ammonia
cleaner on a
soft cloth (not a paper towel which can scratch) and gently wipe the
keypad.
And I always recommend that you use the vent fan when cooking on the stove top to keep heat, steam, and
grease out of the controls.
If it does not dry out
over time, it may need to be manually dried or blown out.
The keypad may be
damaged or worn out, or control unit may be damaged.
The
first thing I would suggest is a hard reset. Unplug the unit for a
minute or so. Then plug it back in, set the clock and try again.
If that doesn't work,
leave it unplugged for about 5 minutes.
Let us know what you find out.
Please reply back with your brand and model number as well as a more specific description of the failure (when & how) so we can help you.