something's happening to my gearbox.

dunno if its normal, tho i thought modern gearboxes dont do this....

its esp apparent when I shift into 3rd.
If I push the gear lever to the front-most position (as u do when u upshift from 2nd-3rd), as soon as I get back on the accelerator, the gear lever "springs" back about 1cm (backwards).

and if I try to push the lever back to the front-most position again, it springs back asa I get on the gas.

it also happens a bit on 4th, not so much with 1st/2nd gear.

WTF???
I hv been very gentle on the g/box, always heeltoe on downshifts. hardly engage into gear too quickly or slipp clutch on hill starts..

whats happening???
(I hv a 5-sp 2.7L btw) i think its not a problem with 6-sp cos I test drove one b4 with no probs.