attribute as contract ref does not resolve

Develop with TokenScript
1

If I want to dynamically get the address to send a transaction to, I cannot do so as the ref will not resolve.

Take the following:

<ts:attribute-type id="lendingPoolAddress" syntax="1.3.6.1.4.1.1466.115.121.1.15">
  <ts:origins>
    <ts:ethereum function="getLendingPool" contract="LendingPoolAddressesProvider" as="address">
    </ts:ethereum>
  </ts:origins>
</ts:attribute-type>

Fed into this action tx:

<ts:action>
    <ts:name>
        <ts:string xml:lang="en">Deposit</ts:string>
    </ts:name>
    <ts:attribute-type id="mintAmount" syntax="1.3.6.1.4.1.1466.115.121.1.36">
        <ts:name>
            <ts:string xml:lang="en">Amount to Deposit</ts:string>
        </ts:name>
        <ts:origins>
            <!-- e18 is a hard coded multiplier.
            rationale for hardcoding: avoiding over-design  -->
            <ts:user-entry as="e18"/>
        </ts:origins>
    </ts:attribute-type>
    <ts:transaction>
        <ts:ethereum function="deposit" contract="lendingPoolAddress" as="uint">
            <ts:data>
                <ts:address>0x6B175474E89094C44Da98b954EedeAC495271d0F</ts:address>
                <ts:uint256 ref="mintAmount"/>
                <ts:uint256>1101</ts:uint256> <!-- placeholder referral -->
            </ts:data>
        </ts:ethereum>
    </ts:transaction>
    <style type="text/css">&style;</style>
    <ts:view xml:lang="en">&supply.en;</ts:view>
</ts:action>

The contract being set to the lendingPoolAddress as attribute cannot be resolved