It's too bad this assert actually fails sometimes with ODPOR :)
{
kernel::actor::ActorImpl* actor = kernel::EngineImpl::get_instance()->get_actor_by_pid(message->aid_);
xbt_assert(actor != nullptr, "Invalid pid %ld", message->aid_);
+ xbt_assert(actor->simcall_.observer_ == nullptr || actor->simcall_.observer_->is_enabled(),
+ "Please, model-checker, don't execute disabled transitions.");
// The client may send some messages to the server while processing the transition
actor->simcall_handle(message->times_considered_);