Did you initially install 2020 and product update 1 or just 2020? 

If you installed both initially, did you reinstall the product update after reinstalling?

It isn't quite the same but here is a KB on an issue with converting the IM_LotSerialTransactionHistory table on 2020.1 and there is a hotfix for it.

support.na.sage.com/.../viewdocument.do

Thanks for your response. I believe I did install an update before I uninstalled Sage, but I'm not sure if it was successful. Once I reinstalled it I did not download any updates. The current version is 6.20.0.1.

I tried downloading the hotfix you linked but it's stating 'This program fix is available only for Sage 100 2020 with Product Update 1 installed, therefore, it will not be installed.

Did you do an a fresh install to a new location?  It sounds as if you tried to install on top of your previous install

Yes I think you are correct, I selected the same install folder when I reinstalled. I'm going to try and download the update and see if that fixes the issue. If not, do another install in a new location?

The update seems to have fixed the issue.

thanks.