Towers and shoot/targeting is so messed up !!!!!

i understand that towers atk enemy champs if they atk opposing team in range of tower........ but lately countless games i play in i am seeing the total opposite !!!!!!

i am seeing a lot of games where enemys charge or atk well in tower range and towers atk minions or enemy champs that are not hitting opposing champs instead !!! it has cost so many games .... i am constantly seeing it in rift and aram ....... <and in a way dominion when u try to leash but as leashing tower shoots u breaking leash>

example: friend playing as soraka gaurding tower , 4 enemy champs charge tower TF atks tower other 3 chase soraka under tower atking/killing and what is tower doing taking few pop shots at minions in range then TF <whom is not hitting soraka.....> the others then all destory tower never once taking a tower shot. wth .....

then just tonight aram enemy team rushes tower we kill them off loosing 3-4 team mates in fight <under and within tower range, and the tower is sitting there shooting minions.....>