"Deal damage to Laser Designated enemy vehicles using lock-on weapons"

I'm absolutely losing my mind over this challenge.... I am using the Mas 148 and it will NOT lock onto laser designated enemies unless they are in my line of sight and even then... sometimes itll miss or randomly explode on air targets... doesn't seem to be working as intended. I've gotten a couple hits but then it doesnt register as a laser designated target hit... im about to lose my **bleep**.