Perhaps Emberson believes he should be getting a better deal, and changed agents to try to achieve that. With news of a rising salary cap next season, all players will be in a better position to ask for more salary.
Earlier estimates this season projected Emberson would be signed for a 3 year contract near $1.5M, but with the cap reaching over $110M within that timeframe, it could be a horrible deal for Emberson himself.
Through 52 games this season, Emberson has continuously improved and settled into his role as a defensive defenceman. He's only got 9 assists this year, but has been an asset on the penalty kill and 5v5 minutes, and the 23 year old will only continue to improve with time.