`pdf_hummus, failed to get image size for ramdisk://image.pdf`

I am including an image in a macro in a style file, with code similar to the following

<assign | header | <macro | ... <image |<tuple|<raw-data>|pdf>|110pt|230pt> > > >

Then I create a document using this package, include a <header> and it works fine.

But

Every time I open the file for the first time, I get the errors

Error: pdf_hummus, failed to get image size for ramdisk://image.pdf
Error: bad image size for ramdisk://image.pdf. Setting 35x35

and the image is invisible until I do Tools --> Update --> Styles.

This doesn’t happen if I directly include that same image in a document instead of through the style file.

What’s going on?

Thanks