Astable multivibrator using op amps - why does it start?
If you give the op-amp even a tiny bit of offset voltage when you connect the uncharged capacitor the output will slam to one rail or the other and oscillation begins.
Similarly, even if perfectly balanced on knife-edge, a microvolt of change in offset voltage will be amplified by perhaps 1,000,000 and the output again saturates, since that 1V becomes 500mV at the non-inverting input.
It’s possible for simulations that use too-ideal components to fail to start oscillating. Giving them a minute ‘kick’ or preventing them from seeking a perfect balance in the first place may help.