Same here I have 12 and it’s only the one it may be a soil issue due to the fact I’m running different soil mixes due to lack of resources if it doesn’t get better i may have to look into other solution could be mites in the soil I’m guessing
It’s been high 80s low 90s I started watering heavy when it got hot so not sure if it’s just from heat or over watering the rest of the plant are all fine