The plb_temac_v3_00_a core occasionally causes the FIFO overrun interrupt to be asserted when it should not get asserted. This problem only affects PLB_TEMAC when it is built for FIFO mode; Scatter Gather mode does not exhibit this problem and is not affected by this patch.
This problem has be resolved in the following patch (please refer to the "change log" for additional information):
You can download the latest "plb_temac_v3_00_a" patch from the following link:
To install the patches, follow the instructions provided in (Xilinx Answer 23474) - "How do I install a patch for the Processor IP Core in EDK tools?"