Currently, when a file is shared on a Microsoft Teams chat, there is a sharing card with two buttons: Preview and Edit.
When the recipient of the shared link clicks on Edit first, an error is shown saying "Office Online failed to load", which apparently is caused by the lack of edit permissions to the file. In other words, clicking the Edit button doesn't add the necessary permissions.
On the other hand, clicking on the Preview button works fine and file is displayed as expected. After previewing, clicking on Edit also works because apparently the recipient of the shared link is added as a collaborator when previewing the file.
Currently there's no indication that users should click on the Preview button first or add the recipients as collaborators directly on Box, so it's confusing for users.
Ideally, the Edit button would also add the necessary permissions before opening the Edit screen.