This is an Xposed module with a workaround for Android Bug #58097. It replaces the getCallIntent() method of com.android.contacts.common.CallUtil with a version that creates a android.intent.action.VIEW intent without a specific component set instead. This is not exactly what earlier Android versions used to do, but ACTION_CALL_PRIVILEGED is for some privileged apps only now, so we can't use that anymore.
The binary version is available on the releases page.