I've been present a few times when it's happened, but nothing in recent memory that springs to mind, especially not at home.
The last one I recall was Northampton away in 2017. Then I think we did at least one pitch invasion in 02/03, though it might have been 2 or 3. And then when we beat Cov on pens in 98 I think we did too.
Overall I think we (Blades specifically) have developed a greater respect for the players and their safety, compared to some other teams. But some of that behaviour has evolved generally, and moved away from pitch invasions, and towards pyrotechnics. Which is a whole other can of worms.