If you are drunk, release heat, and attack someone and declare a cause to be fighting for, then you lose all the heat that you had released.
I tried this twice and AmberRune tried it once. It happened all three times.
If you are drunk and attack with heat without declaring a cause, then you get to keep your heat.
If you have heat released and attack with a cause, you also keep your heat.
It's only when all three conditions are met that you lose heat.