The automaton has different timers for different types of spells. They almost never casts 2 of the same type spell in a row. If the automaton had just cast cure on you, it's going to take roughly 5 seconds before it comes back up on the priority list. As for the haste, whm/rdm puppet have a priority list on buffs. Usually goes Protect, Shell, then Haste, etc. Also, buff spells are also subject to the timer/rotation of different spells, so he'll likely cast an enfeeble in between said buffs.

When you were at 25%, had it just cast cure on you already within the last 5 seconds or so? And what other buffs were up on you besides haste?