[TYPO3-Solr] Custom Index on tt_content is not refreshe automatically

[Holger]

I emptied the queue once again to check the dates.

the first entry of an item when I initialize the queue has the 'tstamp' value of tt_content in the field  'changed' in table tx_solr_indexqueue_item. 
And after changing some values of the tt_content element in the backend, the 'tstamp' value changes but not the 'changed' value in table tx_solr_indexqueue.

Thanks
Holger