What does “it tastes *bright*” mean?

I would guess they meant strong, or potent.

Usually means strong, can be overwhelming

In cooking, the term bright is used to describe something tart, crisp or fresh that is often used to cut the fattiness of a dish or add a flavorful contrast. Think of a plate of fettuccine Alfredo topped with chopped fresh parsley. The crisp green of the herb cuts the fatty flavor of the pasta sauce.

When someone says that a flavor tastes "bright," they're usually referring to a taste that is vibrant, lively, or even refreshing. In the context of cumin, it could mean that the spice adds a zesty or tangy element to a dish. 🌶️🍽️