@Saif Almodares, Thanks for posting in Q&A. For our issue, it seems the Adobe Acrobat Reader is not considered as a policy managed app. So the file open with this app is blocked.
To check on our issue, please firstly check if there's any app protection policy applied to Adobe Acrobat Reader on the affected device under Intune diagnostics log:
If no, please redeploy the Adobe Acrobat Reader app via Intune to see if the policy can be applied.
If the app protection policy has applied to the device, please check the Intune diagnostics log to see if the setting we configure is correctly applied to this device:
Please check the above information can if there's any update, feel free to let us know.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.