Sadly, the two worlds where I encountered this have been deleted with the arrival of the new version of the mod I am using, I will upload it if it ever does it again, but so far no problem with my last two worlds, apart from a possible memory leak (lags more and more, had to close it before it freezes my computer).
This memory problem seems to be recurrent and caused by massive amount of "forced" refresh.
Following DF screen for 250 Z-levels down, then up, down and up again, it started to update far less frequently even before reaching the bottom the first time.
Like after any other problems, closing the window (pressing ESCAPE in my case) will flush the lag, but reopening it will cause the window to come back in the state it was before closing, thus having huge lag from the beginning (even my mouse cursor on my screen only updates every 10 seconds or so when it is in this state.
After some further tests, it appears that the memory used by the process DwarfFortress.exe will take a huge memory space upon opening the program through DFHack, as it uses the same process, and the memory will rapidly go up if following the DF screen.
Furthermore, the allotted memory is not flushed upon closing StoneSense, and opening it again will cause an other batch of memory grant.
What is amazing is that it made DF memory usage go far over my personal record with Firefox of 1.5GB (made it to 2GB before I forcefully closing the thread).
I could upload the world I did it in this time if you really want this, but I had the same results with other modded and un modded worlds, so I doubt it is coming from that.