It appears that org-detangle is broken. I am using spacemacs, but even with a vanilla Emacs (emacs -Q) it appears to be broken.
When I tangle a file with =:comments link= every things works as expected and the comments are added in the tangled file.
When I just detangle that tangled file, everything get detangled as expected.
If I change one or two lines, it normally works as expected.
If I change more than 4 lines, I always get the error message "Not in a block file".
Some debugging shows that the function =org-element-at-point= sometimes tag the element as =paragraph= instead of =src-block=, like if it doesn't know where it is... somehow.
Does anybody use that function without experiencing this (apparent major) issue?