Bug or Bad Mechanic regarding Prey T10

Time: Always
Frequency: Always
World name: Hyperion
Character name: Anubis Kuro
NPC name: N/A
Monster name: N/A
Class/Level: LVL 50 SCH
Party or solo: Party
In-game time: 7PM PST
Area and coordinates: Turn 10 Final Coil of Bahamut - Indugud Boss

I don't know if this is "working as intended" but I feel that not being able to do a mechanic because of RNG is a bug.

Steps:
1. Enter ad phase
2. Daughters of Indugud cast prey on two party members
3. I use Adloquium on both party members. Let's say Adloquium hits for 900HP.
4. One daughter dies
5. Second daughter casts prey on one of the same party members which are still under the effects of Galvanize (from the previous Adloquium).
6. The galvanize effect will wear off BEFORE Prey, so I cast Adloquium again on the target before Prey hits.
7. The second Adloquium hits for less than 900HP, so the Galvanize effect is not refreshed.
8. Prey lands on the party member 1 second AFTER galvanize finishes and the debuff is set.

Connection Specs
- Type of internet connection/provider: 15mb
- Modem maker/model number: Provided by ISP

Model Number of the PlayStation®4 You Are Using
- Model Number: Irrelevant