Can't not transfer mules with plat

So I used to move my mules around the shard to buy/sell stuff from AH in different shards. Today I tried to move my mule and it says "You can not transfer this character because this character has too much coin for the character's level," This is obviously new because as of last week I was able to move him around. Was there an announcement? What are the level/plat requirements to be able to transfer shard now?

Edit: This was a level 16 mule. I assume level 65 characters will have no issue, but I have a few level 50 alt/mules so just curious what are the new rules regarding shard transfers and plat.

Can't not transfer mules with plat