TMS320F280049C: PPB ISR sometimes stopped

Hello TI-Team,

I am using the ppb for zero crossing detection and sometimes, just sometimes, the ppb ISR is stopped from being called, in mean a total loss, not single events which are not called or called to late. The PPBEventStatus is set to 7 and the event is not triggered, seems like the device would lose an interrupt and since the event status is not cleared the ISR is not called anymore, which could be caused by other interrupts in INTERRUPT_ACK_GROUP10 blocking my pbb ISR to be called and calling  Interrupt_clearACKGroup(INTERRUPT_ACK_GROUP10) or is it a problem when multiple events are triggered fast after eachother? The voltage soc is triggered with about 51 kHz. 

My code:

void initZeroCrossing( void )
{
    uint16_t zeroRef = getZeroRefVoltage();
    // Map ISR functions
    Interrupt_register(INT_ADCB_EVT, &crossingZeroISR);
    // Enable specific PIE & CPU interrupts:
    Interrupt_enable(INT_ADCB_EVT);
    // Asscociate PPB1 with ADC_SOC_115_VOL
    ADC_setupPPB(ADCB_BASE, ADC_PPB_NUMBER1, ADC_SOC_115_VOL);
    // calibrtion offset to detect zero
    ADC_setPPBReferenceOffset(ADCB_BASE, ADC_PPB_NUMBER1, zeroRef);
    // clear register once
    ADC_clearPPBEventStatus(ADCB_BASE, ADC_PPB_NUMBER1, ADC_EVT_TRIPLO
    | ADC_EVT_TRIPHI | ADC_EVT_ZERO);
    // Enable crossing zero to generate interrupt
    ADC_enablePPBEventInterrupt(ADCB_BASE, ADC_PPB_NUMBER1, ADC_EVT_ZERO);
}



// my ISR:

static __interrupt void crossingZeroISR( void )
{
    doSomething( );
    // error detection
    crossingZeroCounter++;
    
    ADC_clearPPBEventStatus(ADCB_BASE, ADC_PPB_NUMBER1, ADC_EVT_ZERO);
    
    Interrupt_clearACKGroup(INTERRUPT_ACK_GROUP10);
}

Now my question: 

Since missing single zero crossing events is not to bad will ADC_enablePPBEventCBCClear do the trick or is there a better way to do it? 

Is the explanation valid, that the interrupt is overflown? Can I somehow catch this state? I currently use a counter to detect if the interrupt is not triggered anymore. 

Furthermore: ADC_SOC_115_VOL is soc zero, this is not the problem in this particular case?

Thanks in advance.