"This procedure proved to be very convenient and..."
Is it OK? Can a procedure proved to be convenient? Or should the sentence be paraphrased as
"This procedure was proved to be very convenient and..."?
The original is standard phrasing, at least in American English.
Her love for chocolate would prove to be her undoing.
The decision proved to be a fortuitous one.
That procedure proved to be a convenient one, far easier to implement than the prior method.
[not a teacher]