I got an X4 kit [V4] last year and I’ve mad a fair bit of progress in assembly. My Order No. 13216.
I can’t completely finish my build because I found a big problem.
In this Kit two inside Legs do not fit into the corresponding slots of the Lower plate.
This inside Legs are 3.20 mm thick and do not fit slots approximately 3.0 mm wide.
The outside Legs go in without problem.
Please replace two inside legs by with
a normal thickness of about 3.0mm.
I can send these two defective Legs back to your address and you will be convinced of their flaw.

I want to buy a Power Seat Comfort size L/XL and I hope you can put these two new inside legs with a normal thickness in this package. In addition, I need a second power Switch.
I still hope to fly this summer season. I will be grateful in advance for a faster solution to my problem. Sincerely, Ivan Bovdur

You need to direct message the guys, Paul or Zach or email them. They may take quite a while to reply. I would just stick with the slightly thick leg pieces and carefully sand the tabs down that 0.1mm on each side. On mine the clearances were very tight. Maybe zero, but not negative.