I think this is a bug, but wanted to make sure I wasn't doing something stupid before I posted it as such.
At r32878 (git 1eb605a), Even added new logic for dealing with raw 32-bit AIG blocks. I've got an AIG raster that has a few blocks where valid data is getting set to the min Int32 value (-2147483648) when doing a gdal_translate to GeoTiff.
gdal_translate -of GTiff ai_bug ai_bug.tif
Note the "old" way of getting these values was providing the correct values in this case: