height map values look different in viewport vs. exported map

I'm seeing an issue where the values being exported, a full range of 0-1 black to white, do not match the exported map, which either seems to have the gamma adjusted somehow, or values clamp or leveled up somehow, etc.  This is repeatable, other relevant info and listed below...

• Substance Painter version
  • 2021.1.1 (7.1.1) build 954
• exporting height based on the grayscale channel
• I've tried both 16 bit and 8 bit exports with the same results
• TIFF is the format and Raw is the colorspace
• I don't see any adjustments to set on export in terms of gamma or color correction, so I wouldn't think that's relevant
• is it possible that Painter is computing the different workflow methods I'm using while looking correct in viewport, are not being calculated correctly on export?
  • e.g.- I use several passthrough layers to make overall adjustments at the top of the layer stack at times, that is the case here
  • e.g.- I use anchor points pretty consistently because I enjoy adjusted one layer to affect many, there's some wacky stuff I'm doing at times

Thanks,

Harp