They told me to write here this issue even though I don't think it is a bug. Basically, on Playstation 4, the charge attacks of the Wither (during the 2nd fase) causes all the blocks around to fall on the ground, causing a massive lag which makes it impossible for the player to defeat effectively the Wither due to the lag (I think it goes under 10fps). To replicate this, just spawn the wither underground and make it go down to half-health, now the Wither will start charge attacking you destroying every block around him, making them fall on the ground. One solution could be that everything he destroys with those attacks do not drop, 'cause by now it's nearly impossible to beat and I lost weeks of work because of this.

I will link two videos I uploaded on YouTube from my PlayStation (YouTube doesn't let me download them unless I pay premium, sorry) 

https://youtu.be/KrOeRUVdeHg 

https://youtu.be/ZRizuhUa6IU