Mine did this when I bought it, moving the shifter side to side was stiff and sometimes squeaked, especially when hot.
I took apart the shifter linkage at the gearbox end, removing the linkage pictured at the top of the image below.
One end of it attaches into the little white bushing on the gearbox, pictured (disassembled) in Louis' picture. The other end attaches to the selector on the gearbox under a rubber boot.
Remove this rubber boot (which will probably split, rpd sell them) and clean out and regrease the interfaces between the linkage and the gearbox/selector. Might as well install the new white bushing while you're there.
This solved the problem for me, now the shifter is always nice and free. If you don't have an undertray, get one installed just to help keep extra crap out of the shift linkage.
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