If it was a pest like scale, you would see the bug itself, not just the damage. Although the punctate tiny hard shelled black scale that we here often refer to as Palm Scale (there are many MANY types of scale, both hard shell and soft shell, its hard to know them all so we have nicknames even if they are not really correct) will leave a hole like that after they are killed and removed mechanically. But if you had scale you would see the bug.
I have 6 terrariums, and have problems in a couple with chlorosis on upper leaves of some plants due to them getting just too much of a grow light that is too close. All my big plants grow out in a large greenhouse in all natural light.
I know what you mean by it getting darker. It takes longer to reach us here in Florida but the days are definitely getting shorter. We call it the Slow Season instead of the Grow Season. I fertilizer with long acting time release this week for the last time until Spring, which here is about March 1. I hate it when everything slows down, but, its part of the natural cycle.
