Was the old range using a 3-prong plug? New ones are designed for a 4-prong plug, and if you want to use it with a 3-prong, you must follow the instructions to the wiring in the range's manual and strap the neutral/ground.
Your clock is very likely run off of 120vac, while the stove has 240. To get 120vac, it needs neutral. If the ground/neutral are not done right , it could give you some issues.
Long ago when I lived in Germany, I had one clock that would be accurate on Friday, but off on Monday, then, if you did nothing, it would gradually go back to being right by Friday again...my theory was that the people working the weekend were not maintaining the frequency properly, and when the normal shift got back in on Monday, they slowly tweaked the frequency so that their synchronous clock moved back to being correct.
That can be overcome by using a digital clock that uses its own oscillator, but the one I noticed this on counted the power cycles (in Germany, it's 50Hz, or supposed to be!). FWIW, a clock circuit that counts the acv cycles is cheaper, so that is a factor. Some devices designed for international use may have a switch to set for 50/60Hz, and I didn't run the numbers...if yours has, and is not set to the right frequency, the clock would be off...since it's running fast, it could be set to 50Hz rather than 60Hz, so every second, it would count an extra 10 pulses, or 20% fast.