Starting some time in the last month or two, the export of data available at the "/app/exportdata" URL in Quickbooks Online is broken. The export appears to succeed but no longer includes a full history of transactions or other records, making it useless as a full export or backup of our data. I noticed this because the backup files being generated were significantly smaller in filesize than in the past, and I confirmed it by going to the beginning of the transaction journal and observing missing transactions.

I contacted Quickbooks support about this several weeks ago and they opened case 15129174575 but have not provided any updates, and the export is still broken as of today. 

I thought I'd note this for anyone else relying on those exports a part of your data preservation/backup strategy, so you can consider making other arrangements.