On the last steam update, the ability for global leader-boards for speed running levels was added.
Players could race against the clock and ghosts to achieve a record times, although the score for time was saved properly, sadly the ghost data wasn't.
Steam uses a UGC handle to upload ghost data to a leader-board, It seems that this handle gets deleted after a few weeks, this makes the handle switch to an invalid value, causing the ghost data to be permanently lost forever, I have no control over this and wasn't aware until today.
A fix for this issue is on it's way however, this also means that all of the active leader-boards will be wiped, as ghost data is needed for cheating validation.
I highly apologize for the inconvenience and the loss of the speed running scores.
This change will take effect on the next live version