This conversation has been merged. Please reference the main conversation: Lightroom Classic: TIFF compression settings have no effect when Lightroom sends image to Photoshop for editing
I've set in LR: Preferences - External Editing -> Photoshop CC -> Compression TIFF 16bit to ZIP.
Inside LR when choosing to edit a file in PS and saving that file after I've edited, no compression is applied to the TIFF file. The result is always an uncompressed TIFF file.
Which makes the LR preference setting completely useless.