Hi Estaben,
Thanks for posting. If the new Microsoft 365 icons only appear after the app fully opens, it’s usually related to delayed icon rendering or cache issues. First, check if your device has the latest Windows and Office updates installed, as older builds can cause UI inconsistencies.
Second, clear the icon cache by running Disk Cleanup or using the command ie4uinit.exe -ClearIconCache in Command Prompt.
Third, verify that your graphics drivers are up to date, especially on the device where the issue occurs. Outdated drivers can delay icon rendering.
Last, if the problem persists, try repairing Office from Settings > Apps > Installed Apps > Microsoft 365 > Modify > Quick Repair. This often resolves UI glitches without affecting your files.
If this helps, please mark the answer as accepted so others can find it too.
-Carl