The fluffy white stuff is generally lead-sulfate or copper-sulfate.
The sulfate is from the sulfuric acid combining with the metal.
Just a small drop is all it takes. The crimps do not look sealed.
The sulfate is water soluble and the free ions neutralized with baking soda.
Possible the issue has been lurking within the strands for some time and has just recently pushed out.
Yes it does seem odd just to be back in the wire. Usually if the terminal has lost the seal to the case the terminal is first to go. Otherwise I assume the last service somehow got just a touch of acid on that point.