You have to check your submethod grooves and oversizing. It has an oversize setting for all panels on 5mm. If you put this to 0 the oversize will be removed. You need to do this for every cabinet in your project via the single cabinet mode
I have just exported a cut list, upon checking the measurement’s 2 of the shelves (These are single panels in their own right) are showing in my diagram as 950mm wide but when I export they are showing as 955mm.