Exception "Koin application not started" with declareMock in beforeTest

[lukaszkalnik]

Koin 3.5.6
Kotest 5.8.1
Koin-Kotest extension 1.3.0
Mockk 1.13.10

When I include the extension in my tests:

   override fun extensions() = listOf(
        KoinExtension(
            module = testModule,
            mockProvider = { clazz -> mockkClass(clazz) },
            mode = Root
        )
    )

and try to declareMock in beforeTest

beforeTest {
    declareMock<MyDependency>()
}

then, when running the test, I get "KoinApplication has not been started" exception.

I use isolationMode = InstancePerTest.