Are you missing the GL account information for the details of the invoice, or the Summary at the bottom of the posting journal report? The answer is quite different depending on what you are seeing.

If it's the Summary section, all it may be is that the option to print the GL Summary has not been selected for the report. When you want to print any posting journal, there is a checkbox option to include the summary - make sure it is enabled if you wish it to print.

If it's the distribution details on invoices, then that's more serious. Either something has happened to the report tables or files, or the posting journal file is corrupt. That your AR and GL account numbers are correct likely suggests that posting did not fail.

Hoping this is option A...