Yuumi stealth interaction

I have a question about Yuumi and her interactions with stealth like champions like twitch and Evelyn for example, Is it intended for her spell [prowling projectile] to be invisible while she is anchored to twitch/evelynn? I only saw one instance of this and its rather annoying due to the fact is a skillshot that has a high hit rate since you know, you can AIM it and not be able to see it seems ridiculous . I've also seen an odd interaction on her ult but it's fully visible. Any thoughts about this? Is it something that can be fixed? Regards.