water at bottom of fridge

have a beko american fridge freezer model gnev320s, its working and maintaing fridge and freezer temperatures, it makes ice and is running ok. its approx 5 to 6yrs old

BUT water collects under bottom drawer of fridge, every week or so we mop up the water and it carrys on working, but its bugging me as to whats wrong.

we’ve changed the fan in the freezer compartment when it started happening we got an engineer to do this as he said this is the problem, made no difference, it doens’t or i dont think it has a drainage hole in the fridge, it looks like a plastic zig zag (water tank?) with a tube going in top and bottom, could that be blocked? have ordered a fridge door seal just in case its that but with it keeping temp in the fridge dont think it is but will change it just incase.

not sure what the problem is, it works well we have a thermometer in both fridge and freezer and the temps are spot on. It is plumber in and it makes ice and has cold water coming out of the dispensor.

Any idea would be appreciated, as its driving us mad

Juliex