The coverline is just a visual aid, it has no other significance and you can expect it to vary from one cycle to the next.
Looking at your chart, the EWCM on CD19 makes me think you more likely O'd then. If you changed the prediction method to FAM, FF would probably take away your crosshairs today and put them back in at CD19 tomorrow (assuming tomorrow's temp is as high or higher than yesterday's and today's).
You can also override the O day. I did that this cycle (my temps were weird). I figure we should have a better understanding of our bodies than FF's computer algorithm does. ;)