I only ask as that's what mine did and it was my big end bearings
Has the car ever been run low on oil?
The garages logic behind was when your accelerating the power would force the rod down onto the bearing but when on light throttle with no load on the engine it could move more freely and that's when you'd hear the knock
Could be early signs but always worth getting a opinion from a garage as if it is
Was around 6 years ago when I did mine mate
I ended up rebuilding the engine around 4 months later as the crank was damaged from the bearings , I'd remove the crank and get it checked before ordering anything as you may have to rebuild or replace the engine if that works out cheaper
My forged engine cost me 1800 all in back then but that was with a family member who charged me 500 all in for the removal , rebuild and refit of the engine.
I got all my parts from TSR performance and the customer service was 110% so I'd highly recommend them for any engine component's
I've got a build thread from years back
Lees forged mk2
cupra have a mooch through that I think every common mk2
problem that's in existence I had dealt with it with that car, bloody miss that thing