Please bear in mind that I have absolutely zero clue in this because I have never used habpanel and never looked into it, never tried to learn about it.
Nevertheless, I did some looking around
Among other things I learned from glancing at that:
itemValue is the old name, kept for compatibility reasons. You should use itemState
It returns the formatted value of the item, so maybe have you tried doing it without adding the |date:xxxxx and just use itemValue / itemState ?
