Malaysia’s claim that Myanmar has agreed to take back 5,000 Rohingya has raised hopes of easing pressure on the country’s strained refugee system but also drawn alarm from activists over the risks of returning members of the persecuted minority to a place still engulfed by conflict. Rights groups say any movement of refugees into Myanmar – where the military is fighting multiple conflicts and most Rohingya remain denied citizenship – will need to be voluntary and backed by guarantees of safety,...