Quicken auto-created share adjustments that are wrong, and can't be deleted

(Windows 10, latest Quicken version, in fact the software just updated today)

This is a weird one. I opened Quicken today, and suddenly the value of one of our 401k accounts had changed dramatically before I even updated prices. I look and see that, for some strange reason, Quicken has given me negative positions (negative share value) in a handful of mutual funds that I haven't had a position in for years. I can see them in the Holdings window.

Even weirder, I discover that if I click on one of the products (security detail) with the fake/wrong position, I can see a "removed" transaction from a few days ago. This transaction is not a thing that actually occurred - I checked our account online. And here is the weirdest part. The Removed action appears in the mini transaction history window within Security Detail, but that same transaction DOES NOT APPEAR ON THE REGISTER FOR THE ACCOUNT. So I can't even delete it because it isn't in the register.

Anyone else ever encountered this? A ghost transaction, created by Quicken, which does not appear on the register? Or does anyone have any advice?

EDIT TO ADD: I tried to add an Add Shares transaction for the same amount on the same day, to cancel out the bad placeholder entry (like a buy to close). But when I went to add it, I got a pop-up warning me that this was on the same day as a placeholder transaction and that it would not effect my share balance. Sure enough when I saved it, it did nothing to change the situation. Which is really poor software logic by the way - you have a transaction the software added without me, and you won't even let me offset it, let alone edit it, or even see it.