These encounters that you describe used to work properly, however after a variable refactoring, I must have still missed a few old variables. Brando will only approach you if you are "horny", which means being open to sexual encounters.
That is being tracked through choices you make earlier... however, if you don't see him asking you before you get the option to meet up with him, that is definitely a bug.
Currently, I am putting more focus into the engine rewrite, given that all the story script files will need to be re-implemented again. I don't want to make any promises, but I imagine I should be getting close to finishing up the engine rewrite in a couple months, hopefully.
Baku