Would it be possible that recently you have try to delete a Vendor/Customer record or inventory item? the System would prompt a message suggest you have related data and advice to clear data before able to remove the record.

CC-Recycle said:

I just went back to adjust an invoice in the same month and Sage had already cleared the data

CC-Recycle said:

data was cleared from a zero-balance invoice

Sage doesn't clear the data from empty documents. They're just never created. You may have seen a message on screen to the effect that inventory quantities would be updated, but no journal entry will be created. If you're not using inventory, then there's no inventory to update, so it's just a blank invoice.

If the invoice had zero dollars, then there would be no journal entry created. Because there is no accounting effect, the design assumption (from an accountant's perspective) would like have been that there would be no need to change 'nothing' using an automatic adjustment.

CC-Recycle said:

Is there somewhere else I need to go to get Sage to not Clear Data on Invoices

From what you said, I don't believe that the program cleared any data.

CC-Recycle said:

BTW, when selecting tags to add to this post, the window will only scroll to the C's but not beyond

Lots of things in this world operate as if they were sourced by picking the lowest bid.  I don't work for or even near Sage, so I can't help fix that problem.