object_attr_getdump() causes undesired output

[diablodale]

When object_attr_getdump() is called in my code, the output on dumpout is wrong.
Another user also saw this https://cycling74.com/forums/topic/max-6-0-4-sdk/#post-223112

SDK 6.1.4
VS 2015 community
Windows 10 x64

My attribute is a long, data stored in my object struct, and defined with custom getter/setter like:

attr = attr_offset_new("register", _sym_long, ATTR_GET_DEFER_LOW | ATTR_SET_USURP_LOW,
        (method)max_dp_kinect_register_get, (method)max_dp_kinect_register_set, calcoffset(t_max_dp_kinect2, ob));
        object_addattr_parse(attr, "label", _sym_symbol, 0, "\"registration valid\"");
        object_addattr_parse(attr, "category", _sym_symbol, 0, "\"Kinect Registration\"");
        max_jit_class_addattr(max_class, attr);

All features of Max function as expected...until
object_attr_getdump(x, _sym_register, 0, nullptr);

The output sent from dumpout is
ister