Linux (Fedora 23 x64)
Broken: 2.78, latest in git as of 2016-10-14
Short description of error
If you embed a scene within another scene ("use sequence") at any position other than at the start, evaluation of f-curves is incorrect for the embedded scene - values calculated are for the frame number being rendered in the master scene, not relative to the start of the embedded scene.
Exact steps for others to reproduce the error
scene 1) add some kind of visible strip (e.g. text), add keyframe for strip opacity 0 (transparent) at 0s and 3s, 1 (opaque) at 4s from start of scene.
scene 2) insert scene 1 as sequence, at position 2s from start of scene.
result: render scene 2, text becomes opaque at 4s rather than 6s as you would expect.
Example attached - "sub" scene counts from 1 to 5 by way of animated opacities of text strips, but when embedded starting at 2s in the "master" scene it starts counting at 3 because the 2-second offset is not accounted for.
Affects 2.78 and the latest that I have built from git today.
F-curves do not appear to have any pointer to anything that could tell them what scene they belong to, so it is impossible to work out the correct value for evaltime (animsys_evaluate_fcurves, anim_sys.c line 1691).