MSI enabled for an FPGA design without MSI support

Hello,

My FPGA is connected via PCIe to the host PC via a PCIe switch.
According to lspci, the FPGA is MSI enabled.

But- The FPGA has only legacy interrupt. The design does not support MSI at all.

Is it possible that somehow the PCIe switch "enabled" MSI ?

I ran:
Code:rc=request_irq(pci_dev_s->irq, IrqHandlerPacket, IRQF_SHARED,"fio", NULL);and got rc!=0

Thank you,
Zvika