Stopping indesign from rasterizing layers

Hi all, please i need your help again. Let me explain the situation:

I am trying to create a reflowable epub from indesign but there are a few issues i am facing.  I have some long text anchored to grey background, i really do not knownhow the client created it and anchored it but i am told that they need the text to be reflowable while in the grey background. Whenever i am exporting to reflowable epub, indesign tells me it has rasterized those elements. Now, after ratserizing, when i open the epub, those elements have turned to images and then the texts are not very clear. However, its very important that those texts stay reflowable while in the background so that it can be very visible for readers who may be using smaller screens.

Please help, how do i achieve the texts remaining reflowable without indesign rasterizing those elements. Is there any place i can turn off that rasterizing feature or something. Sorry i am very new to indesign and its a very deep learning vurve for me.