PSD with large amount of smart objects no longer compresses saved PNG's

[Scar7752]

If I have a PSD containing more than roughly 75 smart objects, if I try to save a copy of the document as a PNG, it saves an uncompressed version of the image and ignores your PNG compression settings. 

Photoshop since at least the 2021 CC version, Windows 10.

[Scar7752]

Note that using the Quick Export as PNG feature compresses images as intended.

[Stephen_A_Marsh]

When you Save As, it includes all metadata, Quick Export doesn't.

Just to rule out excessive metadata, what do you see if you go to File > File Info > Raw Data on the PNG Save As version?