I am finding the same, and I see a few other posts about the same issue. I have been on with support for about 40 minutes now. As a workaround, I did find that you can still choose the project with a single time entry. Unfortunately, it may just make more work for you in the interim.
It's vital that that all your hours be entered correctly in your books so that you have your customer and project balances be accurate. QuickBooks Online allows you to create timesheets and associate hours to certain customers or projects so that you can invoice your company time to them. I can provide some insight into hours and projects.
There is currently a known issue with selecting projects to assign hours to in weekly timesheets, and our engineers are currently working on getting that resolved. I do appreciate you sharing the workaround you've found, erica b muskoka, as it may help other users assign their hours while the engineering team works on getting this resolved.
I recommend reaching out to the support team outside of the Community, as they can verify your account information in the system in order to attach you to the list of affected accounts. This will make it so that once the issue is resolved, you'd receive an email notification. You can reach out to them using one of these methods:
Schedule a Callback or start a Chat: click (?)Help in the upper right > type and enter "Contact support" into the QB Assistant > click Contact Us > explain your situation > click Let's Talk > choose Get a callback or Start a Chat. Social Media: Facebook or Twitter.
If you have any other questions, feel free to reach out here.