I am in the process of dismantling a few of my sets. I have just taken apart 79002 Attack of the Wargs .   All of the brown plates broke and disintegrated.  I know it's an old set but is this   a     known      problem?                

Yep. It was a thing up until they announced a fix in the formula in 2019. Reddish Brown, Dark red and a few other colors (I think?) were affected.

Edited October 13, 20231 yr by Murdoch17

I think it was just reddish brown, dark brown, and dark red. I've had hundreds upon hundreds of parts in those colors break, but fortunately LEGO will replace those even if you have a large number of them. Unfortunately, if it comes to minifigure parts, those typically aren't in stock past a certain point, so be careful with any torsos and legs in those colors.

1 hour ago, jFox said:

I think it was just reddish brown, dark brown, and dark red. I've had hundreds upon hundreds of parts in those colors break, but fortunately LEGO will replace those even if you have a large number of them. Unfortunately, if it comes to minifigure parts, those typically aren't in stock past a certain point, so be careful with any torsos and legs in those colors.

Rule of thumb (as far as I'm aware) is: If the part hasn't been made in that color for over two years, it usually isn't going to be available for them to send. For most things they only keep parts of any kind in stock for a certain length of time. This period of time might be longer, or shorter - depending on what part it is / the color of the part and other factors.

I will definitely leave my Jaba Sail Barge in one piece . It is all brown parts.

12 hours ago, jonty14 said:

                                                   I am in the process of dismantling a few of my sets. I have just taken apart 79002 Attack of the Wargs .   All of the brown plates broke and disintegrated.  I know it's an old set but is this   a     known      problem?                

Claim them at Lego and demand new.