M4250 LAG status bug

I've encountered a bug in "IT" Web GUI of M4250-26G4F-PoE+ Switch, I'm running Firmware Version 13.0.4.13:
On Switching - STP - Advanced - CST Port Status - LAG page, table shows odd numbers on Designated Cost column. Designated cost column seems to be stuck on to numbers shown (image1), while CSR Port Configuration page displays correct values.
Also for some reason cost of LAG3 is displayed as cost of Interface 0/1 on CST Port Status page (image2) while CST Port Configuration shows correct values once again.

LAG3 was comprised from 4x 1Gb links between two M4250-26G4F-PoE+ switches. Interface 0/1 being my laptop with 1Gb connection. STP Protocol version 802.1w.

I confirmed this by unplugging LAG3 cables one-by-one and Path cost of Interface 0/1 changed 5000 -> 6666 -> 10000 -> 20000. While LAG page the value displayed on wrong row stays at 5000.