Using whose clause with record tests

Should this work, i.e. the second command with the “whose” test?

get properties of clipping 1
	--> {text content:"position", kind:"RTF", class:clipping, owner:{clipset:clip set id -1, position:1}, name:""}
get every clipping whose owner = {clipset:clip set id -1, position:1}
	--> {}

The code does not find the clipping with said owner, although it exists, as shown in the first line.

I could even write it like this, and it still doesn’t find it:

set o to owner of first clipping
get every clipping whose owner = o

Is that correct behavior?

“owner” is a record that’s defined in the Sdef:

	<record-type name="bin in clipset" code="BnCs">
		<property name="clipset" code="ClSt" type="clip set" access="r">
			<cocoa key="itsClipSet"/>
		<property name="position" code="Pos?" type="integer" access="r">
			<cocoa key="itsBinPos"/>

And referenced as a property in the clipping class:

		<property name="owner" code="Ownr" type="bin in clipset">
			<cocoa key="itsOwner"/>

Can someone spot something I do wrong? Or don’t tests on records work like this?