Mini-graph-card: hovering shows no value

I have a few mini-graph-card:s showing various daily statistics, like this one:

image

My problem is when I hover over a day with a max value of 0 (i.e no data at all), the data point for the last day is shown. Unfortunately I can’t grab a screen shot when hoovering, but I can see this behaviour for every similar card I have in my system. I love this card, but this is a bit annoying. Is there a work-around for this problem? A default value when no data is available would be nice to have.