Dear Shubham Yeole,
Good day!!
Apologies for the inconvenience caused and please don’t worry, let’s work together on your concern and move towards a resolution path.
I understand your concern and I would like to convey that I have tested the behavior at my end with Upload File type question which accepts more than 1 files, and I am able to access all attached files even for the responses with the multiple files without any issue either from the Responses tab or responses Excel workbook (where the multiple files will be separated with the semi-column and opening it as complete link will open the first first, and if you manually copy the link before semi-colon, we can open the each attached file).
In this situation, I would like to confirm whether you are able to open the multiple files attached via responses tab in the Form of Microsoft Forms:
Open the Form in the browser> Responses tab> View Results> Go to the responses with multiple attachments> Open the Links to check the outcome.
If there is no problem and the problem happens only when viewing in the responses Excel workbook, I believe the problem should be further investigated by the related development team via collecting HAR logs because there is not any related service incident reported at the Microsoft Service Health dashboard.
I do feel regret for not resolving the problem and redirecting you to the related development team but the fix to your concern can be find out through the HAR logs and suggest you raise a support ticket from the Office 365 admin center, where the related team will investigate the problem further by collecting the HAR logs.
Reference: Get support - Microsoft 365 admin | Microsoft Learn
Note: To create a support ticket, you need to have admin privileges and if you aren’t admin of your Office 365 organization, please contact the admin of creating a new ticket. How do I find my Microsoft 365 admin? - Microsoft Support
Our sincere apologies if there is any misunderstanding from our end and we request you to share the more details with some screenshots for better understanding your situation and guiding you further.
Appreciate your patience and understanding. Have a great day!!
Best Regards,
Sophia