2GP Provider Free Platform Cache

I'm trying to build a beta 2GP package with provider free platform cache (the package has passed security review).   However I get this: 

[Error]: Package creation failed with error:                

                    package: Invalid provider free capacity allocation. Provider Free capacity not available

Any idea why that might be?  Everything works in scratch orgs with the "PlatformCache" scratch org setting enabled.

The cache is defined as:

<?xml version="1.0" encoding="UTF-8"?>
<PlatformCachePartition xmlns="http://soap.sforce.com/2006/04/metadata">
    <description>...</description>
    <isDefaultPartition>false</isDefaultPartition>
    <masterLabel>package</masterLabel>
    <platformCachePartitionTypes>
        <allocatedCapacity>0</allocatedCapacity>
        <allocatedPartnerCapacity>0</allocatedPartnerCapacity>
        <allocatedPurchasedCapacity>0</allocatedPurchasedCapacity>
        <allocatedTrialCapacity>0</allocatedTrialCapacity>
        <cacheType>Session</cacheType>
    </platformCachePartitionTypes>
    <platformCachePartitionTypes>
        <allocatedCapacity>3</allocatedCapacity>
        <allocatedPartnerCapacity>3</allocatedPartnerCapacity>
        <allocatedPurchasedCapacity>0</allocatedPurchasedCapacity>
        <allocatedTrialCapacity>0</allocatedTrialCapacity>
        <cacheType>Organization</cacheType>
    </platformCachePartitionTypes>
</PlatformCachePartition>