Unofficial Rulings/Errata

Holon's Pokémon

These count as Pokémon that have an owner in their names. (Thus, certain Pokémon Tools like Fluffy Berry cannot be attached to them, Ancient Tomb does not negate their Weaknesses, and Powder Protection Ledian's damage reduction applies when if attacked by them.)

This may be a hard pill to swallow (how can a location be an owner? Why isn't "Holon's" in all caps and a smaller font size, like "Rocket's"?), but the original Japanese text is clear on this. The Japanese text used to specify Owner's Pokémon is 名前の前に「～の」("which has "'s" in front of its name"). Holon's Pokémon fall under this category; they are ホロンの<Pokémon>.

The Japan-exclusive PokéPark's Latias is also an Owner's Pokémon.

Kingdra ex δ

Extra Smoke's damage reduction should be an effect on your Stage 2 Pokémon-ex (not an effect on the opponent's attacking Pokémon). Thus, two things to note:

1. Extra Smoke applies after Weakness and Resistance, not before.

2. Swift- or Brick Smash-like attacks (whose damage "isn’t affected by [...] effects on the Defending Pokémon") will ignore Extra Smoke.

This was a mistranslation, and a very hard one to spot — you'd need to be familiar with Japanese grammar and how effects are generally worded on Japanese cards. The Japanese text uses the phrase 受ける, meaning "received by", implying that the effect resides on the defender.

Spinda

Pattern Distraction's last sentence should read, "You can't use more than 1 Pattern Distraction Poké-Body every time your opponent's Basic Pokémon tries to attack."

(Note: the explanation below is long and only affects one specific case in double battles, so you can skip it, or even ignore this erratum, in single battles.)

The phrase "you can't use more than 1 <name of Poké-Power/Body> each turn" is used on a few cards. On cards with Poké-Powers (like Pidgeot's Quick Search), it works as written; the Power is a "hard once per turn", and can't be used again if you have multiple copies of the Pokémon out, or if you managed to move the Pokémon to another zone and back into play.

On cards with Poké-Bodies, the phrase does not accurately describe the intention of the card. It does not mean that the Body can only ever apply/trigger once per turn; rather, the Body only triggers once every time the event that would cause it to trigger occurs. Or, in gamer parlance, the effect does not "stack"; if you have multiple copies of a Pokémon with a Body that triggers on event X in play, you can only apply the Body once every time event X occurs.

Which Pokémon have these "can't stack" Bodies? Skarmory ex, for example, has a Body that triggers on retreating, and since you can only retreat once per turn and there are no effects that increase that limit, "once per retreat" and "once per turn" are synonymous. Umbreon δ has a Body that triggers on Special Energy being attached from hand, and has an entry in the Compendium stating that it's supposed to mean "once per attachment". (You can attach multiple Special Energy cards per turn with Flygon δ, for example). Dark Ampharos has a Body that triggers on Pokémon being evolved, and also has a Compendium entry stating that it's supposed to mean "once per evolution".

The last category of "can't stack" Bodies apply/trigger on attacks. At first glance, it seems like "once per attack" and "once per turn" are synonymous, like retreating, but the DR Plusle and Minun have Chain of Events, a Body that allows you to attack twice in one turn in double battles. Fortunately, most Pokémon with "can't stack" Bodies that apply on attack reduce the damage done (e.g. Intimidating Pattern Masquerain, Hard Rock Groudon ex), and Cheer On is non-damaging and performed as the second attack of the turn, so it doesn't matter; they would not affect Cheer On even if they did apply to it.

This leaves us with Pattern Distraction Spinda, which triggers on attacks by Basic Pokémon, and has an effect even if the attack is non-damaging. So, if your opponent has Spinda Active, and you attack with a Basic, followed by Plusle/Minun's Cheer On, what happens? Clearly you flip for the first attack, but do you also flip for Cheer On, considering Pattern Distraction, as printed, only can be used once each turn? My answer would be yes, in order to maintain consistency with Bodies from Umbreon δ and Dark Ampharos that have received official errata.

(Side note: should Lanturn's Energy Grounding also be once per KO, not once per turn? For that I would say no — even though it's what Magic players would call a "triggered ability", it's on a Poké-Power, not a Poké-Body like Umbreon δ. In the Japanese text, it's a "hard once per turn", like Pidgeot's Quick Search.)

Holon Circle

The last sentence should read, "If an Active Pokémon uses an attack, that attack ends, and discard this card at the end of the turn."

The English wording is a mistranslation from Japanese, which tells you to discard Holon Circle at the end of the turn. Like Spinda, it overlooks the fact that a player can attack twice in one turn with Plusle/Minun in double battles. If played according to the English text, your first Pokémon's attack would do nothing, Holon Circle would be discarded, then Plusle/Minun would use Cheer On uninterrupted, as Holon Circle is no longer in play when it does so. If played according to the Japanese text, Holon Circle would stay in play during both Pokémon's attacks, and both attacks would do nothing.