Whats this effect on this set of opamps?
You have positive feedback of 50% of output swing which determines the hysteresis along with DC offset . Thus a lousy Schmitt Trigger gain stage with low inter-stage gains of 10 then 10%.  Try noninverting input for stage 2. Then you have a linear gain >10... still not useful.

Try gains of 100 for each stage i.e. Rf/Rin=100, then see the improvement on sensitivity of your positive hysteresis by reducing positive feedback ratio to 1% of output swing or R5/R1=100 for a signal threshold of about 1% of 8Vout or 160mV pp hysteresis.

Compare this to a CMOS Schmitt inverter with 3 stages of gain x10 minimum =1000 min and input bias thresholds for hysteresis of 1/3 from Vdd/3 to Vdd*2/3