Reissner–Nordström repulsion is a well known effect since probably around 1920.

A 1982 article discuss similar effect for a point charge

C. L. Pekeris, June 14, 1982

Proc.NatL Acad. Sci. USA

Vol. 79, pp. 6404-6408, October

1982

Physics

http://www.pnas.org/content/79/20/6404.full.pdf See equation 62 for Newtonian potential, which includes a term with potential -1/2G MQ^2/r^2

now compare this with

http://www.cqfyl.com/pdf/lu2.pdf equation 8a

except unlike Pekeris who gave a detailed derivation, C_Y_Lo just put down the result.

I am pretty sure there were earlier papers than Pekeris