Possible wrong weight or CG.
To the Airbus flyers... does Airbus have over-rotation protection to prevent tail strikes?
It has a pitch limiter indication on the PFD, an orange "V" indication the approaching angle of pitch that would incur a tail strike if over rotated beyond the bottom point of the "V".
But there is no flight control law preventing the tail from striking the ground. There is a very small tail skid, but more of a tell tale sign if touched or scrapped.