I’ve got a similar issue with a couple of my plants. I don’t yet know what the answer is but I’m pursuing each of these ideas first;
Increased total plant mass meaning less ferts and co2 to go around
A lack of available biofilm making leaves that had ‘peaked’ more immediately attractive to shrimp, snails and seed shrimp. The fauna has increased it’s own biomass thus outstripping the supply of available food.
The recent use of a marginal extra oxygen supply (oxydator) increasing the pace of organic breakdown
All just not very smart ideas but there’s no harm in running with them for a while
My new, fresh growth remains untouched.
I’m still observing and clipping out many of the affected leaves whilst watching if there’s a change by adding in a large dried Mulberry leaf. If this has an affect then I would favour my second theory and will marginally increase the availability of slow decomposition food sources and ever so slightly increase powdered biofilm -builders e.g. Bacter AE.
I think I would have a couple of major viewing sessions and see if you can spot any of your tank inhabitants making clear, mechanical impacts on the plants first. That seems the easiest and least interventionist thing to do. Shrimp, snails and seed shrimp are all over anything and everything on the other hand - hence extra, distracting natural food source.
Hope you get to the bottom of it
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