RB260GS SNMP wraparound

Hi all
I use collectd with the SNMP plugin to monitor my RB260GS but with high traffic throughput the values didn’t make any sense.
So I started watching the values with:
“watch snmpwalk -v 2c -c IF-MIB::ifHCOutOctets”

Just before 4294967295 (max 32bit unsigned int) the value wraps around. Shouldn’t the HC “High Capacity Counters” be 64bit so the value doesn’t wrap around so often?
IF-MIB::ifHCOutOctets and IF-MIB::ifOutOctets always seem to be identical.
Is this a bug or am I doing something wrong?

Thank you.