Zoroark Frozen Bug in Pokemon BW2

Some major Pokemon BW2 playing guide sites report on the following bug (software error) in BW2.

[ Phenomenon ]

• When player avoid to follow Zoroak (player retuen from cave) in Champion road, Zoroark does not move any more in the next visiting time.
• Consequently, player can not encounter with next events. (can't get Reshiram, Zekrom, Black Kyurem, White Kyurem)

[ Temporary Countermeasure ]

• When player follow Zoroark, do not avoid and follow Zoroark.

[ Occurrence Condition ]

• Already cleared the game once (finished battling with Elite Four and Champion)
• If not yet clear, Zoroak moves normally in the above situation.

[ Current Progress ]

• The problem detector has contacted to Nintendo. Awaiting official reply.

[ Reference ]
Pokemon BW2 Extremity Conquest DB : Bug report, map of Champion road (Zoroak appear around J in the problem)
Pokemon BW2 Playing Conquest Summary Wiki : Bug report