No, not crushing the oats. I constantly watch the level outside the basket and if it gets down from even I shut the element off. Lately I sit in my chair right at the kettle and watch it, turn the element on and off but I wasn't even that far yet. I had literally just turned the element on and could smell the burnt wort instantly. I rarely leave it on during the mash anymore. It doesn't really need much heat to stay at desired temperature. This had exactly 16 gallons of water still in the kettle.
Not understanding where the corn meal looking crap came from.
I have one last shot I'm giving this thing before I start a 3 vessel 1 bbl build. Ordered a chugger max and going to run a T fitting to keep the bottom circulating as I'm feeding the top. Should keep anything from sitting still and keep better temp readings. If I can't get 5 consistent brews it'll be up for sale and I'll build a 1 barrel system.
I'm not an expert but the first thing I find concerning is the recipe.
21# Maris otter
4# carapils
4# white wheat
2# flaked oats
.5# rice hulls
I went back and looked at my notes and for my 20g system the most I've been able to do is 25.75# of grains. And I felt like THAT was pushing it. I used 17.4g of water. So with about the same amount of water you had about 5.25# more grain. Unless our baskets are different I have no idea how you jammed all that grain in there.
And something I didn't note before, not only are you using 2# of oats but also 4# of white wheat. That means about 19% of your grain bill consists of stuff that is known to cause stuck sparge issue. That seems high by itself but I've also heard that some base grains are more prone to cause sparge issues and Maris Otter might be one. I wonder if this were a regular mash tun if you'd be able to drain at all.
But, just with the wheat and oats alone I think .5# of rice hulls is no where near what you'd need. If this were a 5g recipe I'd still say start with a full pound of rice hulls. I tried to find a source on how much to add but nothing came up. I think someone once told me 5% of your grain bill which would at least get you to 1.5# but I can't see even that being enough.
Speaking of which, are you rinsing the rice hulls? I rinse mine to avoid them messing with my absorption estimates. Plus they are very dusty and can really muck things up.
My last two brews with the 20g system were both 5g batches that had 18# and 17.75# grain bills. If your recipe were scaled in half you'd end up with 15.5# grain bill which is close to the batches I just did. Given the wheat and oats you might need to consider this a 5g batch.
I just remembered that I did a wheat wine a few months ago. I had 13# wheat, 6# pale, 1# crystal 40. My notes say I used 1# of rice hulls. I don't think things were perfect but I didn't have major issues.
One last thought, before brewing that wheat wine I think I posted to ask about doing a step mash and the rest period. Someone warned me to not do it. They tried it and it was a gooey mess. Maybe that is what you are seeing?
Again, I'm no expert, just throwing stuff out there. Good luck.