This is an ongoing problem that has been known since at least some time in January. Gorden Kelly, writing for Cosumer Tech and published in Forbes, wrote yesterday,
“03/16 Update: since publishing this story, I've been contacted by multiple readers who have found the problem is still present in betas of iOS 13.4 (the final version of which is tipped to launch this week), so a fix is not coming any time soon. I've also been sent screenshots of extreme examples of this bug with data consumption north of 50GB, which has led to even those on 'unlimited' contracts being contacted by their carrier for stepping beyond their fair use policy. The purpose of Uninstalled Apps is to show the data used by apps that have since been uninstalled (hence the singular categorization) but affected users have ruled this out by resetting these statistics and even resetting their iPhones and purposefully not removing any apps, but Uninstalled Apps data consumption continues to mounts up (some see just kilobytes, others with multiple gigabytes). I have pressed Apple again for a clarification on what is happening with this data consumption. I will update this article when I get one.“
After reading his full article, which I found on Flipboard, I checked my IPhone 11 Pro Max running 13.3.1 and found that “Uninstalled Apps” had put 1.1 GB on my Phone.
you may want to check your phone as well.