Boron deficiency it looks like to me.
Prevention
• Don’t let plants dry out often.
• Avoid nutrient lockout by NOT overfeeding.
• Don’t let humidity levels drop below 25%.
• Use well-draining, aerated soil.
• Add generous amounts of apples, bananas, broccoli, and chickpeas to your compost pile.
Fixes
• Flush the medium and aim for an ideal pH range.
• Mix one teaspoon of boric acid in 4l of water and apply to affected plants.
Hope this helps. 🤟😜