Last week I started to make a Brown and got a stuck sparge. The wort stopped about a quarter of the way through. I had to transfer it to a couple of buckets while I cleared the not so obvious obstruction. I put the wort back to the tun and the same thing happened again, 3 times.
This phenomena has happened before but not nearly as much.
I think that my old plastic false bottom, that I have used for 7 years, is softening under the heat and weight of the mash and pushes the opening against the bottom of the mash tun.
The new screen is stainless and, I presume, will not fail. The new tubing is heat resistant silicone.