by lazy {} causing a cast exception in production / hashmap loosing values after assigning

we have a code that looks somewhat like this small example:

// this is a class that is injected into a view model, it is injected once, as a parameter// it is used in multiple functions in the view model, some of them may happen one after another or even at onceclass UseCaseProvider(repository: Repository) {    val useCaseMap = HashMap<Class<*>, UseCase<*, *>>()    private val clearFiltersUseCase by lazy { ClearFiltersUseCase(repository) }    // maaaany more usecases made in the exact same way...    private fun <INPUT, OUTPUT> register(useCase: UseCase<INPUT, OUTPUT>) {        useCaseMap[useCase::class.java] = useCase    }    internal inline <reified T: UseCase<*, *>> get(): T {        if(!useCaseMap.containsKey(T::class.java)){            when(T::class) {                ClearFiltersUseCase -> register(clearFiltersUseCase)                // maaaany more similar lines                else -> throw IllegalStateException("UseCase not registered")            }        }        return useCaseMap[T::class.java] as T    }}// example usage in the view model: // useCaseProvider.get<ClearFiltersUseCase>().invoke() // .invoke() is always suspend

and we get a class cast exception, null being cast into an UseCase class, any ideas why that might be happening?

we have a similar usecase provider in another module, but instead of using lazy & the register function it just creates and saves the instances in a hashmap once the provider is created and it does not crash, thus my suspicion that somehow lazy is at fault here?

I'm accepting any ideas (race conditions for lazy {}, thread-safety were my only ideas, but I wasn't able to reproduce the crash)