sap.m.PDFViewer (v1.48) in Master-Detail application on a mobile device not showing

Hi,

I am developing a Master-Detail application which should show an embedded PDF in it's detail view. The project is based on UI5 version 1.48, so the new PDFViewer control can be used.
In desktop mode everything works as expected (fig.1)

But on a mobile screen PDF is not showing properly (Fig 2).

The data source property binding at the PDF control is done by OData path.
<!-- PDF-Viewer since SAPUI 1.48 -->

<FlexBox id="fbPDFViewer" 
         direction="Column" 
	 renderType="Div"
	 class="sapUiSmallMargin">
	
         <PDFViewer id="idPDFViewer"
	    	   source="{myModel>/myPDFUrl}"
		   title=""
		   busy="true"
		   showDownloadButton="false"
		   height="700px" 
		   width="95%" 
		   loaded="onPDFLoaded"
		   errorMessage="{i18n>notFoundText}"
		   errorPlaceholderMessage="{i18n>notFoundText}">
	</PDFViewer>
</FlexBox>

Is there any hint, whats going wrong here?
Thank you all!