sbt with extra unmanagedSourceDirectories don't work with Intellij

I use sbt-projectmatrix for a project like this:

// project/plugins.sbt
addSbtPlugin("com.eed3si9n" % "sbt-projectmatrix" % "0.8.0")

// build.sbt
val foo = projectMatrix
  .jvmPlatform(Seq("2.13.6", "2.12.15"))
  .settings(
    Compile / unmanagedSourceDirectories += (ThisBuild / baseDirectory).value / "shared"
  )

// foo/src/main/scala/Foo.scala
object Foo {
  val s = "foo"
  def sharedS = Shared.s
}

// shared/Shared.scala
object Shared {
  val s = "shared"
  def fooS = Foo.s
}

When I import into Intellij, it complain:

Duplicate content roots detected: Path [/tmp/bug] of module [bug] was removed from modules [shared-sources]

Then Intellij don't know Shared.s in Foo.scala (it mark Shared red with error "Cannnot resolve symbol Shared") and don't know Foo.s in Shared.scala.

Any workaround please?

Extra info: In my real project, I have other val bar = projectMatrix.. and foo and bar share some scala source which I put in shared folder

EDIT: Sorry. I have just found that this issue don't related to sbt-projectmatrix: Replace projectMatrix by project in build.sbt => same problem.