Tony Thompson wrote;
This results from excessive recycling of scrap styrene moldings
DA did use regrind plastic when they did kits and parts. The brittleness runs across their parts line. The handbrake sets also suffer breakage issues.
The DA AB brake sets were done by Grandt Line and do not seem to have this problem.
I have over 20 of the DA gons and back in the '90's, they sent me a fair # of replacement parts for plastic that was broken in brand new kits.
I don't think they will still do that.