It sounds like you're dealing with some issues on your Banana Cream plant. The circles on the leaves that are drying out could indeed be a sign of a problem, but let's try to narrow down the possibilities.
First, let's consider if it could be a pest issue. Circles on the leaves could indicate damage from pests like spider mites or thrips. Check the undersides of the leaves for any signs of pests or their eggs. If you see any, you'll want to address the pest infestation promptly with an appropriate treatment.
On the other hand, if the circles are accompanied by drying out, it could be a sign of heat stress or nutrient deficiency. Heat stress can cause leaves to curl and develop unusual patterns, including circles. Make sure your grow area is properly ventilated and that your lights aren't too close to the plants, causing excessive heat.
Nutrient deficiencies can also cause leaf symptoms like you described. Ensure that your plant is getting the right balance of nutrients, especially micronutrients, to prevent deficiencies. Since you're using multiple nutrient brands, double-check that you're not overfeeding or causing nutrient imbalances.
Since you mentioned that the issue is spreading to other leaves, it's crucial to address it as soon as possible to prevent further damage to your plant. Keep monitoring the situation closely and take appropriate action based on your observations.
Good luck, and I hope you're able to resolve the issue with your Banana Cream plant!