Nexus FEX ports report bogus utilization

I've got a problem with Nexus FEX ports throwing bogus Tx/Rx utilization amounts.

I don't have this problem with ports native to the Nexus cores, only on the FEX ports.

I've verified that port speed is detected correctly and that the devices/interfaces have 64-bit counters enabled. There are no similarities of devices connected to the ports throwing alerts. Some are 100MB devices, most of them are 1Gb server / SAN mgmt interfaces. I'm polling the interfaces at 5min, instead of the default 9min.

Interface XXXXXXXXXX - Ethernet124/1/26 on node XXXXXXXXXXX transmitted at 923% of its utilization, which triggered this alert.

Any ideas?