1st thing I would do is to change the order of the 3 strands
- to see if the problem follows that specific strand or if the same strand position (3rd) is consistently brighter no matter which strand is put there
I have an odd situation myself
- bulbs at beginning of strand are dim, but then the rest are bright
I take a dim one out and swap with a bright one from the back half
- bingo: bright becomes dim and visa versa
WTF?