I have to confess that I have commenced a take off roll with the trim in the full aft position (which is normal for taxi / back taxi).
The result took a moment or two to figure out (for me). The stick force was way too far aft. I realized what was going on and continued the take off.
I was able to overcome the trim by pushing forward with some extra force on the stick to achieve the correct attitude. After reaching a safe altitude I corrected the trim setting.
In the accident report the pilot mentions that a new cushion changed his perspective. I will bear this in mind in my future flying.
My total time in the Tiger is pretty close to the pilot in this incident.
When I started flying the Tiger, I had more than one old timer say ” Just watch out when you get to about a hundred hours or so, that’s when she’ll turn around and bite you in the A$$!”

The bump in the runway may have been contributory. The cushion may have been contributory.
The trim lever could also have moved fully aft upon impact (It is spring loaded aft if it comes off the lock on the “cheese cutter”)
The report states that the pilot is not really sure. Understandable after a trauma such as this.
Like most incidents, there are many factors.

Andy Scott