Chunks O Crap floating in my fermenter and some bottles

I have not had this problem up until the last 4 batches. I use irish Moss in my boil and I get a lot of the initial crap (trub) out that way. I cool quickly, usually 30 - 45 mins to below 80 degrees. I pitch the yeast and over the first few days this large crust forms on top then starts floating to the bottom in chunks. I don't get the uniform layer of trub on the bottom like I use to but a layer of chunks of trub and if I move the carboy some of those chunks will float back into suspension, and there's still a small bunch of these chunks on the top when I get ready to rack to the secondary. I experimented and did a batch made of DME only and got the same thing.

2 batches I went ahead and bottled and after a week and a half I looked at the bottled beer and tapped the top and saw that a very tiny bit of trub fell from the top toward the bottom.
The beer tastes fine (except for one batch that over fermented and tastes like rubbing alcohol, actually not bad once you get one down). The other was great. I made 2 more batches and tasted between the first and second fermentation jugs and they were both fine.

I have used different yeasts for each beer, no difference. I also do BIAB (except for the DME batch) and make three gallons at a time because of space considerations and equipment. When I pitch I pitch the entire packet of yeast, which I have always done in the past before this started, without this problem.

One last thing, this started when I reduced my mashing temp from 160 to 154. I was mashing at the high temp due to a thermometer that was 6 degrees off on the low side. For your information it was a walmart electronic probe thermometer. Let's see... Oh and all my last 4 batches FG were under 1.004 A rye that I did came in at .998.

Well that's all I can think of right now, I'm suspecting that this is nothing but yeast because of the DME batch I did with the same results but I can't figure out why this started.

Thanks for any help

  Perhaps the settled trub in your boil pot is being disturbed while transferring or you are not able to remove all the wort without getting some in there.
I use a 6" bazooka screen in the boil kettle, Irish moss, Vortex the heck out of the boil when done by hand with a paddle, recirculate, throttled; while cooling, slowly pump out the wort to the fermenter and gently tip up the kettle when near the end and don't get any trub. I used to get some of that floaties stuff until I really focused on trub removal and now things are great. However you do it, aim to get better at it each time you brew. Upgrades to the system and procedure are constant until you have excellent trub removal results.

I also remove floating hot break scum during the boil and find an improvement in clarity with the  finished product.
Also, temperatures outside of the yeasts prime fermenting temperature may cause clarity and floaties issues.

CHEERS

do you have a way to drop the temp of the fermenter after fermentation is complete and before bottling?  this will drop most stuff out of the mix.

depending on how settled things are when you transfer into your bottling bucket, keep an eye on the bottom of the racking cane... if it drops in to the settled yeast and pulls it up, pull back a bit.

also, if you have to move the fermenter in order to transfer to the bottling bucket, give it a few minutes to settle back down if you see floaties come up. 

that's about all i got for now, hopefully some little subtle tweaks that will help improve your process.

Yeah what Jtoots says is important, I take it further. My fermenters are placed in an elevated location from day one and don't move at all until  the contents have been syphoned or, drained from spigot. Careful syphoning with a special syphon tool that draws from above the syphon tube is critical. This way you don't  disturb the sediment and yeast accumulations at all. Sometimes it is helpful to put a cheesecloth ball on the sypon outlet hose to act as a filter screen in case any floating yeast particles do get picked up.  Cold crashing after transferring further helps clarify the beer.
CHEERS