Problem with Importing PDF - gradations and darkening of Images

Hoping someone can shed some light on a problem we have been having with Importing PDF's into Corel - We have 2018 Graphics Suite - but also downloaded the free trial edition of 23 and still having the same problems.
Some images have like a Dark Shadows or filter over them when imported that isn't showing in the PDF. - Also the images with Gradations are being cut off when the gradation starts so end up with only part of the image showing. - When importing these into in-design there is no issue at all - so suspect its got something to do with how Corel imports them as layers - and is editable. - I saved the PDF as a postscript file and imported it, - it was better but had chopped some of the images up randomly where the overlap etc.
Pictures as examples in below link
 https://drive.google.com/drive/folders/1-uhxFo8ExM3fhoc5FEU8tbgNgq77HLkF?usp=sharing