This is easy to reproduce:

• lfs setstripe -c 1 -i 0 /mnt/lustre/a
• dd if=/dev/zero of=/mnt/lustre/a bs=1M count=1 conv=notrunc
• chown $ID /mnt/lustre/a

The uid on OST object will not be changed after chown.

Look into the code osp_attr_set():

        /* new object, the very first ->attr_set()
         * initializing attributes needs no logging
         * all subsequent one are subject to the
         * logging and synchronization with OST */
        if (o->opo_new) {
                o->opo_new = 0;
                RETURN(0);
        }

I don't quite see why this is necessary, but seems it'll break chown in above situation: OST object is created in 'dd' operation, and the first attr_set operation after create is the 'chown', and it's skipped.