Greetings and welcome to the router forum. Thank you for joining us. This is a fairly common problem so this might be your solution.
When you loosen the collett, keep backing it off till it feels tight a second time. Now loosen it again with your wrench and if this has been your problen your bit will come right out. I don't remember how I learned this for my router, but I just did somewhere.
Wisdom: Where experience and knowledge combine and become one.
"We are all one decision away from Stupid!!"
"How often we sacrifice the permanent plans of God on the altar of immediate solutions"
I have a very good memory, just short is all.