Testing on Ignition 8.1.50…
We’ve got a standard tag provider setup with “Allow Back-fill Data” enabled, and have tags which often get backfill data (i.e. with a timestamp before the current/recent value). The backlog values get put into the history tables just fine, and don’t trigger alarms or change events. 
When I look at the raw SQL tables, I see the backlogged values have a dataintegrity of 0x100C0 (65728) instead of the normal GOOD of 0xC0 (192). When I query the tag using queryTagHistory, I have to do it with ignoreBadQuality set to false or the backlog values aren’t shown. There is no easy way to get the return format as wide with only “good” values if I want to include the backfill. The best method I can see is to get the results in tall mode, filter on the quality ourselves (backlog tags show up with quality=203 in tall mode), and then transpose it back to wide mode ourselves.
This feels very wrong to me, especially since “Good_Backfill” is listed in the “Good” quality code table in the manual: Quality Codes and Overlays | Ignition User Manual
Is this intentional or an oversight?