Can a parent be found in contempt for interfering with the other parent's phone calls during parenting time?

It's possible, but it depends heavily on what the order actually says. Contempt requires a clear, specific term that was deliberately breached, so if the order or agreement explicitly addresses phone or video contact during the other parent's parenting time, a parent who intentionally blocks or interferes with those calls could face a contempt motion on the same basis as interference with in-person parenting time. Where the order is silent or vague about communication during parenting time, bringing a successful contempt motion becomes much harder, because there's no clear term to point to as having been breached.

This is a good example of why the specific wording of a parenting order matters well beyond the visitation schedule itself; provisions about phone or video contact, if the parents want them enforceable, need to be spelled out clearly rather than left as an unwritten expectation. A parent experiencing repeated interference with calls should document each instance, including dates and any response from the other parent, and get legal advice on whether the existing order supports a contempt motion or whether it needs to be clarified first through a different process.