Skoda yeti gearbox

Hi. New here. Had many skodas over the years my first yeti had for 6 years, apart from a spring never gave any bother. Bought a new yeti and since day one had bother selecting 4th gear on occasions. Got new gearbox replaced when car 12 months old and all been fine for 6 months. Now noticing 4th gear sticky won't select the gear yet again. Either try several times to engage or lift up clutch and press and try select again. No pattern when happens can be hot or cold very random. 

Any other yeti owners experience similar problem. 

Thanks Brian