The cooldown time could be an separate issue, but that's not what OP claimed. A proc'less run of 12 charges w/ a 35% chance per charge is not likely (not saying it didn't happen), and there was even another anecdote of 37 charges with no proc, so something else may be blocking it. The only other thing that can block a weapon proc besides the chance is the weapon proc cooldown timer. For a little while, this will be temporarily visible so we can figure this out.

Roll a die 12 times, how likely is not getting a 1 or 2 in the entire run? Even with the random chance, after 12 rolls, you should still statistically 1 or 2 several times.

Help me help you.

-ALS