can't access custom metadata in fluid template

[heisenbol]

I'm using yag 4.0.7 on typo3 6.2.19

I've setup custom metadata and want to print it out in my template for each image. I tested something like

<f:for each="{listData}" key="rowIndex" as="listRow">
<f:debug title="DEBUG4">{listRow.image.value.itemMeta}</f:debug>
</f:for>

the itemMeta contains among others

customMetaData => 'a:1:{s:6:"people";s:3:"xxx";}'
customMetaDataArray => array(empty)

so customMetaData does contain my custom metadata in a serialized form, and I expected customMetaDataArray to contain the metadata in an array. But it is empty.

I also tried something like

<yag:eachCustomMetaData item="{listRow.image.value}" showEmptyFields="1">
TITLE:{customMetaData.config.title} DATA:{customMetaData.data}
</yag:eachCustomMetaData>

I get the title of the metadata, but I can't get the content of the the field. Shoudn't customMetaDataArray contain the unserialized data? Or customMetaData.data?