No, that actually happened. We all watched it happen in realtime, emails were leaked confirming it, but by that time we all already knew what was happening.
This isn’t some crazy conspiracy by the way, lawsuits confirmed there was a clear DNC bias, but they were dismissed because the DNC argued it was their right to choose a candidate and the impartiality in their charter was determined to be a political promise, not something enforceable in court.