If you use the format "yyyy-MM-dd" type in a full value and go back to change the year part the focus changes to the month part.
For example enter 2022-01-10 and then go back with the mouse to the year part. Type in 20. The focus then changes to the month part before completing the year part.
This happens with other formats as well when you use MM. The leading zero seems to screw things up. If you play around with the control and changing stuff you will notice that the focus function does not work.