How consistent is your CO2 concentration in the water? Is it the same an hour or so after the lights come on every day? Many of us have seen that allowing the concentration to vary widely, like running low for a day, will lead to BBA, as you have. I quit using DIY CO2 when the variations in concentration due to one of my bottles needing to be changed, was followed by a persistent BBA attack. As long as I was extremely careful to change a bottle before I say any bubble rate drop I had no BBA and was very happy. Once I was a bit late a couple of times, the BBA showed up. And, this was with low light.
A clue to why this happens is that plants manufacture their enzymes to match the conditions they are in. With significant CO2 they use one set of enzymes, but with very low CO2 they use a different set (different amounts). When the CO2 is inconsistent the plants have to readjust their production taking energy away from growing tissue, and, poorly growing plants invite BBA. This is not proven, as far as I know, but fits the data.