What was the dimension of the tab on the new one?
Try to install the running boards on my 3/23 build R1S and faced the same issue on the driver rear.
Another issue was on the passenger front, can not get the bracket to sit flush, look like the hole shifted by 1/4 to 3/8.
I emailed the support...
That is what it does when I enable it this mode from beginning but after a week it stay in kneeling mode while in drive, good thing I noticed and manually change to normal height.
Adding this to my service appointment in middle of May.