MacBook Pro M4: Office Group files not discoverable

I am experiencing an issue on my MacBook Pro (Apple Silicon M4) running macOS Tahoe 26.2 where files stored in the Microsoft Office Group Containers directory

(/Users/XXXXX/Library/Group Containers/UBF8T346G9.Office/pictures)

are accessible only via an exact file path. These files do not appear in Finder search results and cannot be enumerated or discovered by applications such as Microsoft Excel during file search operations.

I intentionally placed the image folder in this directory because my Excel macro loads images programmatically without triggering repeated file access permission prompts. When the same images are stored in user folders such as Documents or Pictures, macOS prompts for access on a per-file basis, which disrupts the automated workflow.

The same macro code and folder structure function correctly on my iMac, which suggests a difference in macOS sandboxing, privacy enforcement, or Spotlight indexing behavior on newer Apple Silicon systems and macOS versions.