What your camera is calling HDR is really just a single-shoot underexpose-and-digitally-boost-the-shadows mode that other cameras might call highlight tone priority or dynamic lighting.
True HDR, in my mind, is the combination of mutliple exposures in a seamless fashion, which the newest cameras can also do, although any motion between the multiple exposures can lead to ghosting.
The trouble with single-shot "HDR" is that there is often significant shadow noise, which the true HDR does not have as much trouble with since the shadows come from an exposure where they were already bright enough and don't need digital brightening.
Using EXIFTool I am able to see that your RW2 file has metadata indicating Contrast Mode: High Dynamic, so is flagged for Panansonic's softare to process differently.
EXIFTool can also extract the camera-embedded preview (I used EXIFtool GUI for this) which has the camera's HDR-treatment applied, and from what I see there is significant color noise splotching in the darker portions of the image, especially the wood of the foreground building:
For comparison, here is what you're seeing when importing the raw data into Lightroom -- I have used the Camera-Raw plug-in which has the same tone adjustments as LR:
However, if you start with the raw data, it is possible to improve on what the camera has done, both in regard to better noise-reduction as well as better sky definition and smoother transition to the sun. You might make different choices than I did, but the point is that you can make different choices than what the camera did:
Adobe products have no way to "know" what Panasonic is doing for HDR mode so they don't try. What opening raw files in Adobe products does allow is freedom to be beyond what the camera has done for its JPG.
This is always the choice of accepting the camera's treatment from a JPG or the freedom to change or go beyond the camera processing using a raw converter.
