Left drive shaft hitting outdrive

[Zipper]

I'm new to the X6 and after re-building a 2nd hand one I am a little puzzled about the left driveshaft. It's running the Associated V2 shocks, but the left rear shock will not fully compress, as the driveshaft is hitting the inside of the out drive. Is this normal? Do people just add a washer to the outside of the shockshaft to stop it happening?

Thanks all.