Sequencer Inputting non-existent Location Data

I was testing the Sequencer in UEFN and made a sequence that only tracked the location data of the X and Z coordinates on a cube. I then closed the sequence, moved the cubeI tracked along the y-axis, and when I reopened the sequence and played it, it remained in the same Y-axis as when I had animated it.

But then, when I moved the object along while having the sequencer open, it worked as I thought it would, working regardless of where on the Y-axis I moved it as it is not being tracked. Is this a bug? And if not, does this mean that if I moved this object and then played the sequence it would move the object back to its position within sequence when being animated or in the new position? Thanks.