Pages is showing OBJ on top of of the images icon when I export it to EPUB on my iphone.

I found the answer to this here:

Iclould Pages EPUB Tag on Images Read on … - Apple Community

Basically copy the icon  and do a search and replace. (If you don't see the icon, you can copy it from here: https://www.compart.com/en/unicode/U+FFFC

To copy and replace, I used Sigil, but the OP used Calibre. Either should work. If you've never used either, just open the ePub in either and go to file, search & replace, select all files, and replace the  icon with a space or nothing.

Hopefully, Apple will fix the bug in Pages, but until then, this is what I will do.

These are fellow user supported public communities and the Apple product teams do not participate here. That means if you want the Pages product team to know about the  object replacement character showing up in EPUB under certain Pages settings, you need to communicate that information to them. It won't get fixed based on posting it here.

On the Pages application menu, use the Provide Pages Feedback menu item to make the product team aware. They may send you an email asking permission to pursue this with you for additional information.