Short answer—- I don’t know whether we’re talking a dish name issue, as @chandavkl alluded, or a ingredient/stylistic issue.
Longer story…
I’ve had Sichuan liangfen, thick mung bean starch noodles with a spicy sauce, at a few restaurants, and made Carolyn Philips recipe at home, but don’t know how that differs specifically from the “sad” version. The Chinese characters for Chengdu Taste in SGV indicate sad (@chandavkl , other than probably being excellent, do you know if their version differs in a fundamental way from other versions?).
Here’s what I wrote in my early-2017 abandoned attempt to track dish names, for which I salvaged at least Sichuan noodles at 61 restaurants.
“I’ve separately listed two types of liangfen, mung bean jelly, but I think they refer to the same dish. Are Northern Sichuan mung bean jelly 川北涼粉 and Heartbreaking mung bean jelly 傷心涼粉 the same? I planned to combine them, but Berkeley’s Chengdu Style lists both dishes. I dug up some lore about where the latter gets its name-- there’s even a trademark dispute. Carolyn Phillips has a recipe for a Guizhou version of mung bean jelly, and gives some comments about how to make a Sichuan version.“
Your best bet might be to head to Berkeley’s Chengdu Style, try their sad bean jello, and use the opportunity to chat with students 
I’d also check menus on the newer places I listed on the regional list as having Chongqing chefs, which tend to have some newer Chengdu dishes than standard canon.
Here are places that list the dish under the Chinese name “sad” 傷心 as of 19 months ago. On a case by case basis, I have no idea how those differ from another 40+ places which call it Sichuan or spicy liangfen or something.
Chef zhao Spicy hot jelly noodle; 傷心涼粉
Chengdu style Sad Bean Jelly (very spicy); 傷心涼粉
JX cuisine GreenBean Jelly Noodle in Chili Sauce; 傷心涼粉
Spicy way Rice Jelly in Hot and Spicy Sauce; 傷心涼粉
