Looks like a leak, but it may be caused by a shell extension rather than Opus itself.
The first thing to do is to track down how to trigger the leak on your system.
Sometimes leaks will be caused by some of these things:
- Going into a certain folder.
- Going into folders with certain file types (or with a particular file that triggers the problem).
- Right-clicking certain files or file types.
If you can work out which file or folder triggers things, we can then suggest things to try to see if it is Opus or a particular shell extension causing the problem.
It's also possible to use VMMap to track the leak to a particular component, but some people have found it doesn't work great on newer versions of Windows. (Windows 10 at least. Not sure if anyone had problems with Windows 8, which it looks like you're using from the screenshot.) That's detailed here if you want to try it: How to find components causing memory leaks.
Also: Which version of Opus are you using?