Failed matching mocking signature for open suspended functions

Expected Behavior

I expect my test to be green when testing open suspended functions in an abstract class

Current Behavior

The unit tests are failing to match the mocking signature

Failure Information (for bugs)

From the code snippets below, we have a SingleTestA where we inject an instance of SingleTestB which extends an abstract class AbstractTest, AbstractTest includes an open suspended function suspendedOpenFunction, when verifying the testB() function we get the exception below.

The tests succeed when removing either the open keyword or the suspend in the method suspendedOpenFunction.

Stack trace

Failed matching mocking signature for

left matchers: [any()]
io.mockk.MockKException: Failed matching mocking signature for

left matchers: [any()]
    at app//io.mockk.impl.recording.SignatureMatcherDetector.detect(SignatureMatcherDetector.kt:97)
    at app//io.mockk.impl.recording.states.RecordingState.signMatchers(RecordingState.kt:39)
    at app//io.mockk.impl.recording.states.RecordingState.round(RecordingState.kt:31)
    at app//io.mockk.impl.recording.CommonCallRecorder.round(CommonCallRecorder.kt:50)
    at app//io.mockk.impl.eval.RecordedBlockEvaluator.record(RecordedBlockEvaluator.kt:63)
    at app//io.mockk.impl.eval.VerifyBlockEvaluator.verify(VerifyBlockEvaluator.kt:30)
    at app//io.mockk.MockKDsl.internalCoVerify(API.kt:145)
    at app//io.mockk.MockKKt.coVerify(MockK.kt:244)
    at app//io.mockk.MockKKt.coVerify$default(MockK.kt:235)
    at app//com.sixt.one.base.architecture.issue.SingleTestImplTest$test test$1.invokeSuspend(SingleTestImplTest.kt:31)

internal class SingleTestImplTest {

    @MockK
    private lateinit var singleTestB : SingleTestB

    @Before
    fun before() {
        MockKAnnotations.init(this, relaxUnitFun = true)
    }

    @OptIn(ExperimentalCoroutinesApi::class)
    @Test
    fun `test test`() = runTest {
        val sut = SingleTestA(singleTestB)

        sut.testB()

        coVerify { singleTestB.testIt(any()) }
    }

}

class SingleTestA(private val singleTestB: SingleTestB) {

    fun testB() {
        singleTestB.testIt(SingleTestB.Intent("test"))
    }

}

class SingleTestB : AbstractTest<SingleTestB.Intent>() {

    data class Intent(val str: String)

}

abstract class AbstractTest<T> {

    fun testIt(intent: T) : Flow<String> {
        return MutableSharedFlow<String>().onStart {
            suspendedOpenFunction(intent)
        }
    }

    open suspend fun suspendedOpenFunction(intent: T): Boolean {
        return false
    }
}

mockk / mockk