Android release build crashing trying to load sgen

I am trying to build an Andoid release build for my Xamarin.Forms project, but I keep getting the following error:

[monodroid] Trying to load sgen from: /data/app/com.mycompany.myapp/lib/arm/libmonosgen-2.0.so
[mono] The assembly mscorlib.dll was not found or could not be loaded.
[mono] It should have been installed in the `/Users/builder/data/lanes/2058/58099c53/source/monodroid/builds/install/mono-armv7/lib/mono/2.1/mscorlib.dll' directory.

Anyone else run into this and know how to fix it?