Size of cell changes when calling it from a function?

I am calling a function like this:

for z=1:3       
if z==1
            [GUD,GUDID]=H1(ID2,HHPerson,nBEV,BEV,x,Hcombos,Household,sample,A);
        end
        if z==2
            [GUD,GUDID]=H2(ID2,HHPerson,nBEV,BEV,x,Hcombos,Household,sample,A);%run('H2')
        end
        if z==3
            [GUD,GUDID]=H3(ID2,HHPerson,nBEV,BEV,x,Hcombos,Household,sample,A);
        end
        
        save(sprintf('Allv/Alla/AAG%d',z), 'GUD');

The output "GUD" should always be 1000 doubles of the size 1x1000. But the output for z==3 is

1x798 double 1x766 double 1x767 double 1x763 double

I have checked by debugging in the function H3, it constructs GUD with a 1x1000 double at a time, but it is when I am calling the function that it gets wrong.