Image Replacement

So...it appears there's no way to replace a single JPEG image. Resolve keeps seeing my replacement image as an image sequence. I can change how Resolve sees sequentially numbered images, but only within Resolve. There's no such setting for the Windows dialog that comes up when using the Replace Selected Clip command.

I can import the new image and change it out for the one in the timeline, but this error should be addressed. I should be able to Replace Selected Clip on a JPEG image in the timeline.

Resolve Studio 15b5
Windows 10 Pro (1803)

While it behaves like this on a Mac too, what is the problem?
The still has "freeze frame" automatically applied in the timeline, and when I replace it, it stays like that. So, even if the software "sees" a whole sequence, the frame I choose is the one shown as a still.

It's not working as it should. That needs be addressed.