"blunder by" is an acceptable phrase in written English.
It is used to refer to a mistake or blunder made while doing something. Example: "His inability to recognize the situation was a huge blunder by him."
Did the Sun blunder by backing Cameron?
55 mins: Another blunder by Hangeland!
This eminence didn't protect her, however, from a shameful and deplorable blunder by the BBC.
A serious blunder by unions, managements or politicians could make an election impact.
MbS's rivals see the war as a blunder by him and an opportunity for them.
Rivera, ever classy, then tried to soften Wilpon's blunder by saying, "You never know".
"The Supreme Leader committed a historic blunder by putting all his weight behind Ahmadinejad.
He did not turn out to be a huge blunder by management.
A horrendous blunder by Mertesacker presents the ball to Aluko, who goes around Fabianksi.
Now Oakland is building its own stigma, brick by brick, blunder by blunder.
It turned out to be a colossal public relations blunder by Time Warner.
