TMS320F28335: ADC conversion error?

Part Number: TMS320F28335

Team,

Could you help with the below?

We are seeing ADC conversion errors (more than 130 LSB) despite that auto calibration is done during the ADC initialization.
Any ideas?

See below the code snippet.
// ADC calibration

    EALLOW;

    SysCtrlRegs.PCLKCR0.bit.ADCENCLK=1;

    (*ADC_Cal) ();

    SysCtrlRegs.PCLKCR0.bit.ADCENCLK=0;

    EDIS;

        /*

     * Configuration ADC, mode SEQ

     */

    EALLOW;

    #define ADC_MODCLK 0x3 // HSPCLK = SYSCLKOUT/2*ADC_MODCLK2 = 150/(2*3)   = 25.0 MHz

    SysCtrlRegs.HISPCP.all = ADC_MODCLK; // HSPCLK = SYSCLKOUT/ADC_MODCLK

    SysCtrlRegs.PCLKCR0.bit.ADCENCLK = 1;

    EDIS;

    AdcRegs.ADCREFSEL.all = 0;              // Internal reference

    AdcRegs.ADCTRL3.all = 0x00E0;           // Power up reference/ADC circuits/sequential sampling

    DELAY_US(5000L);

    AdcRegs.ADCMAXCONV.all = 12;                // 13 analogue channels

    AdcRegs.ADCTRL1.bit.SEQ_CASC = 1;       // mode cascade SEQ 16

    AdcRegs.ADCTRL1.bit.ACQ_PS = 15;        

    AdcRegs.ADCCHSELSEQ1.bit.CONV00 = 0x8;  // ADCINB0

    AdcRegs.ADCCHSELSEQ1.bit.CONV01 = 0x9;  // ADCINB1

    AdcRegs.ADCCHSELSEQ1.bit.CONV02 = 0xa;  // ADCINB2

    AdcRegs.ADCCHSELSEQ1.bit.CONV03 = 0xb;  // ADCINB3

    AdcRegs.ADCCHSELSEQ2.bit.CONV04 = 0xc;  // ADCINB4

    AdcRegs.ADCCHSELSEQ2.bit.CONV05 = 0x0;  // ADCINA0

    AdcRegs.ADCCHSELSEQ2.bit.CONV06 = 0x1;  // ADCINA1

    AdcRegs.ADCCHSELSEQ2.bit.CONV07 = 0x2;  // ADCINA2

    AdcRegs.ADCCHSELSEQ3.bit.CONV08 = 0x3;  // ADCINA3

    AdcRegs.ADCCHSELSEQ3.bit.CONV09 = 0x4;  // ADCINA4

    AdcRegs.ADCCHSELSEQ3.bit.CONV10 = 0x5;  // ADCINA5

    AdcRegs.ADCCHSELSEQ3.bit.CONV11 = 0x6;  // ADCINA6

    AdcRegs.ADCCHSELSEQ4.bit.CONV12 = 0x7;  // ADCINA7

    AdcRegs.ADCTRL2.bit.EPWM_SOCA_SEQ1 = 1; //  ePWM4

    AdcRegs.ADCTRL2.bit.INT_ENA_SEQ1 = 1;    // 

    AdcRegs.ADCTRL2.bit.INT_MOD_SEQ1 = 0;    //