ms-word command decoded the WebDAV URL before sending to server

We implemented our own WebDAV server as C# HTTP handler running on IIS.

We are using below URL to open the document in Word via WebDAV server.

ms-word:ofe%7Cu%7Chttp%3A%2F%2FMyWebDavServer%2Fwebdavproxy%2FTest%2FSampleTestDocument.docx

We explicitly encoded the URL before invoking document URL via ms-word. This request is successfully reaching in the C# WebDAV handler, but the URL path is automatically decoded by ms-word before sending to the server which is not expected(/Test/SampleTestDocument.docx). We have verified it in Fiddler, URL is decoded by client machine itself before sending to the server. Due to this, server code will again decode the requested URL and it will cause a double decode issue. This issue is occurring in few machines only, majority of machines, its working fine.

Any idea, Why some version of Microsoft Office is automatically decode the URL before sending to server?