This seems absurd from a company offering backups as a service.

Especially if they allow them restoring all your data onto a drive and shipping it to you, they pretty clearly should have enough information available to them to test restorations of data, and the number of times I've heard that failure mode ("oh, we didn't track deletions well enough, so we only found out we deleted it when you tried restoring"), plus them saying they have made improvements to avoid this exact failure mode in newer client versions, makes me think they should have enough reports to investigate it.

...which makes me wonder if they did, and decided they would go bankrupt if they told people how much data they lost, so they decided to bet on people not trying restores on a lot of the lost data.