Just downloaded the new version: 20170127
Now PhotoFlow is much more stable with the Stamp Clone tool !
Unfortunately, it still crashes but much more later than before. As a consequence, the messages by the prompt produce a huge log text file this time before the crash : 30 Mb 
Another problem is stritcly related to my personal hardware setup:
Windows 7 - 64 bit
CPU : Intel I7
RAM : 8 gb
GPU : Nvidia graphic card
In short, with my Raw Nef images (Nikon D700 - 8-9 Mb each) there is always a big lag between the click to apply the stamp clone and the final result on the image. But I suppose I should buy a much powerful computer to avoid this lag with big Raw Nef images
Tested on Windows 10 - 64 bit as well (to confirm the problem on a different computer)
CPU : Intel I7
RAM: 8 gb
GPU: Nvidia graphic card
On Windows 10 today's version is indeed much more stable !
It still crashes though but only if you really continue with the stamp clone tool to do so...
I don't link the log txt that I got with message prompt because it is huge (210 Mb; with 7000000 rows...)
BTW , both on Windows 7 - Windows 10 I have noticed that sometimes you lose some clicks when you clone the image. In short, the stamp clone action is not applied on the image.
It occurs on random but it is bothering because you are forced to repeat once again your action. At first, I have supposed it was a lag due to my big Nef images (8 - 9 Mb) but now I have realized that you really lose them and you have to repeat them.
Thanks a lot for your work.
Aside from this particular crash PhotoFlow is indeed amazing !