I've used PDF::API2 but I haven't used PDF::Table previously.

I checked your population of the $cell_props data structure - all good - no problem there.

The documentation for PDF::Table talks about conflicts between background_color_odd, background_color_even, cell_props and header_props and how they are handled. I suspect your problem may lie in this area.

I'll also point out that the difference between the colours #F5F5F5, #F0F0F0 and #E0E0E0 is minimal and I wouldn't rely on visual inspection to differentiate them. You may already know this.