There seems to be a bug on the PlayStation 5 where downloaded software from the PlayStation Store gets stuck in the queue. You'll be informed that the game is queued for download or an error occurred, but then nothing will happen. The next logical step is to restart the download. However, when some users who encountered the issue tried to fix it, the software they're downloading is nowhere to be found. And when they try to visit the store, their purchase is wiped, and they're being asked to buy the title again. The issue seems to be happening with different titles, suggesting it's a problem with the PS5 itself.
One quick fix from your end would be to factory reset your console. Thankfully, the PS5 is new, and cloud saving is now available. But with the size of games to download, the process can be troublesome. Sony hasn't commented on the issue yet. But if this issue is more widespread, we're expecting to hear from them soon, hopefully with a better fix in tow.
Source: T3
Sony has released a better, and hopefully, more permanent fix to this issue. We detailed it in this post.