ataquanta- vb. "refall, fall second time, double fall" (sic in PE17:166). The correct gloss must be "refill, fill second time, double fill", which would connect with the verb quanta- "fill" and also make rather better sense.
Quenya
ataquanta-
verb. *to refill, fill a second time, double fill
ataquanta-
verb. refall, fall second time, double fall
A word appearing in notes from 1959 as a combination of at(a)- “double, second time” and quanta- “fill”, but Tolkien translated it as “refall, fall second time, double fall” (PE17/166). Helge Fauskanger suggested the translation should have “fall” >> “fill” (QQ/ataquanta).