Inconsistent response to links to pdf files

[Guest]

On a web page I have links to various pdf files stored in SharePoint.

For instance:

<a href="https://xxxxxxxxx.sharepoint.com/:b:/g/ERDg259NvlJEu-QUuuem3cMBBnNwciy2yBm1fQhM7MUDfQ?e=KoGsYT" target="_blank">RFC Constitution and Rules (2017)</a><br><br>

<a href="https://xxxxxxxxx.sharepoint.com/:b:/g/EciqDAu4w2pKv-tNxYX3rNoBPnN5SdPcAZewvh1OTn-IGw?e=NDL7sH" target="_blank">RFC Policies (2017)</a><br><br>

My browser (Firefox) is set to open pdf files in Reader.

Strangely the first link opens the pdf document in a browser window, the second link opens the pdf document in Reader. To me this implies that the first document is somehow avoiding the browser default setting. How can this be?

Any ideas?

[try67]

This is something you'll need to ask the developers of Firefox. Adobe has nothing to do with how the browser identifies files and what it does with them.