Characters in uploaded file name are being replaced with underscores

[Timothy Balk]

When using Outlook, uploading attachments to OneDrive we've been seeing random characters being replaced with underscores when they are finally placed in OneDrive. Not really any correlating information right now as it happens with long file names and short file names. Various document types as well. Has anyone else seen this happen?

Thanks

[#2]

No, it shouldn't touch the file unless these characters are special characters? Also the actual file name is getting modified or the filename in the URL?

[#3]

@Chris Webb It fully changes the file name over. Actually had this one happen to a co-worker, she was doing a demo uploaded a file named TestDocument.docx attached to an email and in OneDrive it's now ____D___m___.docx ... So really weird behavior.