Beardie always black beard

[Beardie2020]

I rescued a beardie from some rubbish conditions he's settled in well to begin with and was calm and still is, however he's constantly got half black beard, this has been for the last week, I havnt changed anything that I'm aware of, last time I seen it was when I first got him, and he was fully black and dark pattern on belly for few days till he settled, ever since I've done nothing but improve the life I can offer him, brought new accessories and hides etc for him, given him a proper diet, he still eats fine etc and he hasn't shown any blackness etc just can't for the life of me work out what is causing him to be stressed, he's been like it for about a week, and moves around just as much as usual, just hasn't gone to bed for last few days, he just stays in his hammock and sleeps there, there something wrong but I don't know what normally he will sleep under his hammock in the dark where I can't see him.
I havnt changed anything with his bed, apart from substrate but I didn't do this til after he stopped sleeping in his usual spot incase there was a smell putting him off, as him likes to poo through the holes in his hammock above , replaced with the same usual substrate
Only other thing changed is he won't chase crickets, but will still eat them if hand / spoon fed

Any advice would be good, feel guilty I'm not offering him everything he needs, something is missing or needs changing but I have no idea ‍

 

[Josh]

Can you tell us more about his setup? His heat source? Maybe more pics of him and his enclosure?