My unmaxed U-21 goalie returned from training camp so I went to sell the backup keeper (maxed at 8 pucks) because I don't need him anymore. Clicked "Yes" to say I am sure about this decision, and suddenly realized I had put my unmaxed keeper on the transfer list by accident instead of the maxed one.
So now I lose my best U-21 goalie and possibly future U-23 guy as well. As a cheap, homemade, domestic player he is irreplaceable.
Could be worse though, I can buy an expensive foreigner instead later when a slot opens up.