Mocking suspend function Kotlin with MockK causes endless loop

Question

Mocking of the code executed inside async {} block, goes to endless waiting.

the code under the test, where databaseClient.x.y.z should be mocked:

suspend fun findByFilter(statement: String, rowCount: String, pageable: Pageable): PageImpl<Geoitem> =
    withContext(Dispatchers.IO) {
        val geoItemsList = async {
           databaseClient.sql(statement)
               .map(rowMapper::apply)
               .all()
               .asFlow()
               .buffer(bufferSize)
               .toList()
        }
        val totalCount = async {
           databaseClient.sql(rowCount)
              .map(singleValueMapper::apply)
              .all()
              .awaitSingle()
        }
 }

the code in unit test:

@Test
fun `should execute SQL query and counting query in parallel`() = runTest {
    // given
    // THIS block causes endless loop
    coEvery {
        databaseClient.sql(pagedSql).map(rowMapper::apply)
            .all().asFlow().buffer(100).toList()
    } returns mockk<List<Geoitem>>()

    // THIS block also causes endless loop
    coEvery {
        databaseClient.sql(countSql).map(singleValueMapper::apply)
            .all()
            .awaitSingle()
    } returns 1L

    // when
    repository.findByFilter(sql, countSql, PageRequest.of(0, 20))

    // then
    coVerify(exactly = 3) { rowMapper.apply(any(), any()) }
    coVerify(exactly = 1) { singleValueMapper.apply(any(), any()) }
}

any attempt to mock the code inside suspend function goes to endless loop. How should I do it properly?