R8000 Traffic Meter ceased to operate with Firmware Version V1.0.4.12_10.1.46

Well, I've tried everything I could think of - played with every setting and factory reset it etc - all to no avail. So I reverted it back to V1.0.4.4_1.142 and Bingo - the taffic meter works fine. So I tried the upgrade V1.0.4.12 again - traffic meter bust. Reverted again to V1.0.4.4 - Traffic meter works fine. Then upgraded direct from the downloaded file rather than by using the router upgrade option - Traffic meter held the old figures but wouldn't update at all. Now reverted yet again to V1.0.4.4 and, youve guessed it, all is working fine. Weird but I refuse to spend any more time on it unless someone has any ideas...........????????