Why do my photos look flat or washed out in Lightroom?

This is a Lightroom rendering issue, not a problem with the file. By default, Lightroom can apply its own develop settings on import that override the color profile embedded in your AutoHDR photo, making it look flat.

Two things to fix

• Set camera raw rendering to "Embedded & Sidecar." In Lightroom, go to Preferences → Performance and set Camera Raw rendering to "Embedded & Sidecar." This tells Lightroom to use the color profile embedded in the file rather than generating its own preview from scratch.
• Remove any default import preset. If you have a develop preset set to apply automatically on import (Preferences → Import → Apply During Import), that preset is overriding the embedded edit. Set it to "None" so your AutoHDR edits come through clean.

After making those changes

Re-import the photos — they should match what you saw in AutoHDR.