I was told by Epic’s devs that there is currently a bug with remote building for distribution.
Basically it fails to validate the certificate so its fail over to the next certificate, which is probably in your case the developer certificate. Which fails of course.
Hopefully it will be solved in 4.19 but as far as I know it hasn’t fully solved yet.
Btw, they also emphasised that “HIGHLY” recommended to use a Mac for distribution builds (especially for the App Store). Except of this bug, for instance, some of the shaders are compiled on the device instead of precompiled on the computer, which make textures and material look blurred until it finishes… which can be annoying.