I do not believe i have encountered that issue before.  Since you went to 2021.2, that would mean that you used the DB upgrade utilities to get to 2021.0, and then applied the 2021.2 product update.  If you try this again, perhaps you can go to only 2021.0 and see if the problem exists there first, and if no, then apply the product update to see where it might be happening.

Sage Support could probably also help you out.

In general, I would be sure to download and install the latest Sage 500 ERP database utilities from Sage's download site.  The RTM versions can be upgraded over time and it is best to be sure you are using the latest version.  Get any version of the utilities that you will be upgrading to, which is in your case 2021.

You more than likely encountered a logged error, but if the database upgrade did not inform you of an error I would still check the log. I have seen this kind of stuff many times, usually when the database or test system hasn't been prepared properly, you use an unsupported version of SQL, you have custom modifications or in at least 1 case, the system ran out of storage space. Preparation has to include not only resource allocation to SQL (especially tempdb) but proper consistency checks performed on the database, index maintenance, space allocation and typically a schema comparison. Sometimes these are only the beginning steps.