Advice of leaf

I am not the world’s most most experienced gardener, but I am pretty good at solving problems and from what I have read that is what it looks like to me. The pictures match up and it isn’t a terribly uncommon issue. This page has a good visual reference. https://dutch-passion.com/en/blog/a-visual-guide-to-cannabis-deficiencies-n987

Keep in mind the cal/mag has nitrogen specially when you are in flowering. Also check your TDS

Thanks all for responses. So to add to others the PH was a bit high at 6.7. this grow is a hydoponics in a bucket. I manually change water over once a week with fresh nutrition from advance nitriencts grow micro bloom. I add dutch pro root at early stage. Also add cal mag now and then

Looks like magnesium bro

Definitely agree with you on the Magnesium deficiency. Now the real question is if it is deficit or a ph issue? Here is a helpful chart for reference! https://www.loudclouds.co/wp-content/uploads/2016/07/marijuana-deficiency-chart.jpg

More info needed ? what method are you growing in and what's the PH & PPM reading in the runoff or reservoir.

Better to check all the plant status ; it seems like a mag def but it can be a nutrient lockout due to a excess of salt in the water

@Andreasbudz, yes it does look a magnesium deficiency. Make sure the PH is correct before adding any nutrients to the medium. Good luck!