I can't say that's something I've seen before, but is it getting plenty of calcium and magnesium?
I fertilize it with maxsea seaweed fertilizer and liquidirt. I tried to find out how much calcium and magnesium but it doesn’t specify that. Should I supplement with a calmag fertilizer?
I'll leave it Ray to supply the details. But from I could read when I looked up liquidirt, it makes a lot of claims but no numbers as far as nutrients go. Consider fertilizing with a standard fertilizer that tells you what is in it. In most of California, calcium and magnesium aren't a problem, they are naturally in the water. (If you are in San Francisco, where the water is very pure, you might need to use a pure-water formula that includes cal/mag. The rest of us get liquid rocks out of the tap )