Invalid signature error for MicroG repo apps

[ghost]

Foxy Droid gives "Could not validate, invalid signature" error while trying to install MicroG Services Core from the MicroG repo. Installing the same app via official F-Droid client works fine, as well as downloading the .apk file from the MicroG site. So far this is the only app i've come across to give this error, but since the official F-Droid client works fine i would think the problem is on Foxy's side?

[xxxxme]

Confirmed: Foxy Droid 1.1, 1.2 & 1.3 fail to install anything from the microG repo, complaining of an invalid sig. F-droid 1.10 (latest) works properly.