Saving large files within parfor loops

i am trying to save variables >2Gb to separate .mat files from within a parfor loop. I have written a parsave function and explecitly called '-v7.3' from within my parsave function. See below.

function parsave(file,camData)
    save(file,'camData','-v7.3')
end

However, whenever the data gets to this point, I get the

"Could not save because data was larger than 2GB. Use -v7.3 to save variables larger than 2GB" warning.

Does anyone know why this is/how I can get around this issue? It seems weird that MatLab calls this issue when I've explicitly told it to act on it.

[Kojiro Saito]

I've tested the following code in R2019b but couldn't reproduce the warning which you got. It works well.

parfor ii=1:2
    a = ones(2^31+ii, 1);
    fname = sprintf("result_%d.mat", ii);
    parsave(fname, a)
end

function parsave(file, var)
    save(file, 'var', '-v7.3')
end

Is there any different from your actual code?