Should my buds be sticky now?

I'm 6weeks into flowering and most are sticky but a few are dry at the top of the bud..... is this normal or is my light burning them? it doesnt look burnt.... 600w hps w cooltube (400cfm can fan) about a foot away BUT its 8"-9" away from the tall colas directly under the light.

anyone help??????

Which buds are not developing the thc? are they lower buds towards the bottom of the plant or the top colas? because if the top colas are the only ones w/o thc production I would use my best-guess to say the light is too close...

but I would say it also depends on the strain, if it is a sativa I would say there is still plenty of time for trichome production

The lower parts of the bud is sticky but the tops are dry.... i figured it was from heat but theres no signs of burning... will they get sticky while curing?