united-states
Will Bob face repercussions for violating his court orders conditions
when it was done with the full active complicity of Alice, if Alice
then decides she would like to use this mutual breach as leverage
against Bob to harm him, or if it otherwise comes to the attention of
relevant authorities?
Yes.
Bob would have committed an offense under U.S. restraining order/protective order law in almost every U.S. state. Orders permitting contact with the consent of the person protected by the order are very rare in the U.S.
These orders can only be lifted with court approval, not with the mere consent of the person protected by the order. It is common in U.S. cases of this type for the judge to specifically tell someone in Bob's position, in open court, face to face, that Bob will face severe sanctions for violating the order even if someone in Alice's position tries to make contact with him or consents to the interaction.
This is done to prevent people in Bob's position from using their long standing ties to the protected person from undermining the judicial process, only to repeat their bad behavior once this has been done.
Incidentally, in U.S. law, the main thing that distinguishes protective orders of the kind discussed, from ordinary court injunctions in other cases, is that violating a protective order is an independent criminal offense immediately enforceable by law enforcement by immediately arresting the violating and then after that commencing a criminal prosecution, rather than merely by contempt of court proceedings in the underlying case initiated by court filings in the underlying cases. This can be done without the permission of, and indeed, over the objections of, the person protected by the protection order, in the discretion of the relevant prosecuting attorneys, even if the underlying protection order is later vacated.
In a usual injunction enforcement case, the aggrieved party files a motion in the underlying case seeking to impose contempt of court sanctions, a prompt hearing is held in the underlying case, and law enforcement enforces the order only by punishing someone found to have been in contempt of court after the hearing is held.