Zabbix Agent running on AIX platform (5.3 and above) is constantly collecting system information using perfstat API:

http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.prftools/doc/prftools/prftools07.htm

This results in Collector accessing Object Data Manager every second which results in ODM accessing files like CuAt. This can be seen when tracing collector's process system calls using command "truss -p <PID of collector>" (e. g. "truss -p 2756952"):

[...]
statx("/etc/objrepos/CuAt", 0x2FF20020, 76, 0) = 0
statx("/etc/objrepos/CuAt", 0x2FF20600, 76, 0) = 0
open("/etc/objrepos/CuAt", O_RDWR) Err#13 EACCES
open("/etc/objrepos/CuAt", O_RDONLY) = 5
shmat(5, 0x00000000, 6144) = 0x40000000
statx("/etc/objrepos/CuAt.vc", 0x2FF20510, 76, 0) = 0
open("/etc/objrepos/CuAt.vc", O_RDWR) Err#13 EACCES
open("/etc/objrepos/CuAt.vc", O_RDONLY) = 6
shmat(6, 0x00000000, 6144) = 0x50000000
shmdt(0x40000000) = 0
close(5) = 0
shmdt(0x50000000) = 0
close(6) = 0
[...]

In this case Collector is collecting additional system statistics that can be accessed using system.stat[resource,<type>] key. Collector should not collect this additional information unless that key is used.