Hello
Yes definitely a sign of calcium....if you're not giving additional calmag i would recommend adding it to your feeding at least once a week. Once i started using calmag regularly my leaves were much happier.
Otherwise look into your ph, if its lower than 6.2 that will lock it out and if it's too high that can also lock out, aim for 6.3-6.6 range if possible.
*possibly do a mild flush to break free any buildup and then come in with a mild nutrient solution at a good ph.👍