Release DURING the sprint????

Yesterday we released... During the sprint. After the sprint start a critical bug was discovered and the planned testing by our own Operations division could not work with the bug. The PO just wanted us to fix a new release. A new release costs. So I asked what we would cut from the sprint. He didn't understand. Finally he got it and we cut one of the new planned features.

It felt like I was the bad guy, not just handing him the fix, but in retrospect I should not have agreed on a release at all. You don´t release during the sprint. You just don´t. I googled it and I couldn´t even find someone writing on the subject. But now I know. And knowledge is king.