I am aware that Moulood is bid'ah and not permissible.

Answer

Functions on 12 Rabiul Awwal are the innovation of the Qabar Pujaaris (Grave Worshippers). Since the Shariah has not fixed this date specifically for lectures, it is wrong, un-Islamic and bid'ah. The fact that there is insistence on attending the 12 Rabiul Awwal talk unsubstantiated by the Sunnah indicates its bid'ah status. If a permissible or even a Mustahab act is elevated above its Shar'i status, then such an act will be classified as bid'ah. It is therefore transgression of the prescribed limits of the Shariah to impose even a permissible practice on a reluctant person. Furthermore, in this era such talks on specific occasions and nonspecific occasions made specific, are given undue emphasis and pressure is applied on people to attend, hence it is not permissible to attend the talk on the night of 12 Rabiul Awwal.