If you have a replay in which some action is impossible for some reason (e.g. because the level changed). Then when loading the replay:
- Upon encountering the impossible action, the game stops replaying any actions, even those that are still possible afterwards.
- The impossible action is however not deleted from the replay action list the game keeps internally.
This has one very unfortunate consequence: If you load such a replay and let it play until the impossible action, then one can continue assigning further skills and solve the level. Afterwards at the result screen one might think about saving the solving replay. However when you load the replay again, the replay stops again at the impossible action (which is still there) and then does not replay any further action. So in effect the saved replay of a solution does no longer solve the level when loaded!
Currently you have to explicitely cancel the replay before the impossible action occurs and then replay all further actions again, in order to produce a working and solving replay.
This happens in V10.12.15-C. I haven't yet checked it in the experimental versions.
It probably still happens.
However, you could also (I assume) fix such a replay by manually removing the offending action, either via the Edit Replay hotkey or using a text editor on the NXRP file.
Easier workaround: Turn Replay Insert Mode on. This bug doesn't happen while that's active.
I'm currently working on an actual fix.
Fixed for next update.