Errors Compiling Using Eclipse Compiler, but not Javac

After upgrading to IDEA 2017.3.4 (and then 2017.3.5) my Java project stopped compiling when using the Eclipse compiler, which I have been using without issue for quite some time. Switching to the Javac compiler allows the project to compile with no changes to configuration or source.

The first errors were "the import XYZ cannot be resolved" and "cannot be resolved to a type" errors related to JavaFX classes. After manually adding jfxrt.jar to the dependencies of my module, this problem was "resolved" and all code in the `src` folder compiles correctly. However, then all my test classes would not compile due to the same sorts of errors related to importing/referencing classes in the source of the project:
"The import XYZ cannot be resolved"

Note: In the case of all these errors reported by the Eclipse compiler, IDEA is not showing any errors in the editor UI (only in "Messages" view) and is able to navigate to the referenced classes without any issues.

Versions:

• Java: 1.8.0_162
• OS: macOS 10.13.3
• IDEA: 2017.3.5

Any ideas on what I might need to change in order to get my project building using the Eclipse compiler again?

Thank you