Gradle: Annotation Processor can't find project dependency

Question

I'm fairly new to Gradle and I have a project which uses JPA modelgen. Said project depends on another project which is our own and the annotation processor can't find this dependency. It has no issues resolving external dependencies.

Relevant part of my build.gradle:

dependencies {
compile project(":my-other-project")

//Omitted irrelevant stuff


annotationProcessor 'org.hibernate:hibernate-jpamodelgen:5.4.18.Final'
}

Now I'm probably missing something super simple, but I can't find the cause of this error, which occurs when building:

symbol:   class [my-other-class]
location: class [my-class]
C:\[path]\:94: error: cannot find symbol
DataProvider<[my-other-class], String> createDataProvider([my-class] service) {
              ^

Now when I start the application, it compiles and runs, just without layouting (this is a Vaadin Java application)