Suppose I play through an AL adventure wherein a potion of flying is found. I know that I or another character can keep that potion, using it during that adventure or saving it for a later adventure. But is the potion of flying unlocked for me to buy more with Treasure Checkpoints if I want? It is on Magic Item Table D, which means it would cost 16 TCP of tier 2 or higher.
In Season 9, one player keeps the consumable
Season 9 of Adventurers League did away with unlocks for all types of magic items (as well as TCP). Regarding consumables, the ALDMG (v9.1, p. 4) now says:
Consumable magic items (potions, scrolls, ammunition, and soul coins) are equitably divided among the characters - resolving disagreements randomly if necessary.
The question still refers to Season 8 specifically, so I'm keeping this section for posterity, even though Season 8 rules are no longer in effect.
In Season 8, all characters unlocked the consumable
The official document Detect Thoughts (version 1.3, page 2, emphasis mine) says:
Regarding Magic Items
When a consumable magic item (that is a potion, scroll, or parcel of magical ammunition, only) is found by the characters, the intent is that a consumable item may be immediately kept by one character and is subsequently unlocked for everyone present (including the character that got to keep it).
According to Community Manager Amy Lynn Dzura in the same link,
The information that we round up [in Detect Thoughts] will find its way into the appropriate documents when the next revision of our documentation comes around.
Unfortunately, the AL Dungeon Master's Guide (version 8.2) currently implies that you don't unlock the item, so you'll want to keep a copy of Detect Thoughts handy until they update the AL DMG.