[ic] loop search empty parameter problem

[Grant]

The following code seems to ignore the first set of parameters which should
cause only the records with a blank value for the user_id field to be
returned.

[loop
search="ml=100000/fi=ebay_sold/st=db/co=1/sf=user_id/se=/op=eq/nu=0/sf=sku/s
e=sku-99/op=eq/nu=0"]
[loop-data ebay_sold code]
[/loop]

If se= is changed to something like se=test then no records are returned as
there are no user_id fields with a value of "test".  There are also no
records with a blank value for the user_id field, so why does
sf=user_id/se=/op=eq/nu=0 return records?

I'm using 4.9.3.

- Grant