Hi Chi chen,
from traces for this error I found that below query. could you please check if this is related subjected error.
I think SDM splits first name with space and queries with middle name however middle name is blank.
firstname: test user
Last name: ticket
middle_name : <blank>
BPMessage
{
method = call_attr
arg 0 = (string)cnt
arg 1 = (string)sync_fetch
arg 2 = (string)RLIST_DYNAMIC
arg 3 = (string)last_name = 'ticket' AND first_name = 'test' AND middle_name = 'user'
arg 4 = (integer)26
arg 5 = (integer)0
reply object = Yp8cBA [Func_exec_catcherSCRNX]
reply method = 1:freeaccess.spl:27773:lookup_where_clause
msg origin = COMPILED_SPELL
}