Erdős problem 1061

For $S(x) = \#\{(a,b) : a + b \le x,\ \sigma(a) + \sigma(b) = \sigma(a+b)\}$, is $S(x) \sim cx$? The preprint claims $S(x)$ grows faster than $x (\log x)^R$ for every fixed $R$, ruling out the linear asymptotic.