Certain Apps in Collections not downloadable to iPad users in Apple Business Manager

I have users requiring the PDFGear App on their ipad's. The iPad's are registered in Apple Business Manager. The PDFGear App has been purchased and added to the Apps and is in one of the Collections that I have assigned to the users. The Users are assigned to the Collection containing the PDFGear App. However the app will not show under the apps listed as being available for the users and is not available for them to download. I added other Apps the same way and found most show up fine and are downloadable, just not the PDFGear App. I have tried loading to App to different Collections, tried adding it to different users, made sure users are added in Collections, checked for compatibiltiy of the App, updated the iPads and am running out of ideas.

Any help from someone having run itno the same problem would be appreciated!