Hi Nick

I think that the build number above has an extra zero in it - it should be 12.24 (Build:20201022.00).

I confirmed that the build number is correct in the version I installed.

Can you check under Site admin > Plugins > Plugin overview if there are any local plugins or plugins that haven't installed

Are there any errors in the upgrade log?

If this doesn't help are you able to create a support ticket with the environment you have and we can look at this in more detail.

Regards