Missing Assembly References in Jenkins Builds

Hey all, I'm getting some unexpected results when building through Jenkins. In the logs, we get a bunch of .dll's returning 'Compilation Failed', and a ton of corresponding assembly reference errors. For example:

I've dealt with these errors plenty before, but this is odd -- these two scripts are in the same folder, using the same namespace, compiled into the same assembly, and I've double-checked that both exist in the project. It seems just like something gets totally busted. It happens to a ton of our assemblies, both 3rd party & our internal code.

Here's the next odd part: the build actually succeeds! It seems like all of these errors happen before the build actually starts (perhaps just when launching Unity into batchmode), and then the build formally starts afterward, with no errors. It's great that it builds, but I'd like to figure out why this is happening -- it makes it difficult to see which errors are blocking builds, and if the builds are actually failing, etc.

 

I moved this to Editor & General Support, since it's not really a scripting issue.