What would cause latex paint to dry cracked in some places? I painted 2 coats of latex primer with a 2 hour drying time between the last coat of primer and the paint.
Hard to say… could be a bad or old batch of paint (or primer)or an inferior grade of either… or possibly a hidden moisture problem within the wall surface material… if you have drywall then latex primer would be OK, but if you have plaster, it would have been best to prime with a Pigmented Shellac Sealer Primer…
If you were painting interior, I have experienced this problem with several causes. One was where the coating was put over a wallcovering adhesive which had not been thoroughly removed. Latex paints will partially reactivate the adhesive and cause cracking. Another instance is where too much paint was applied and could not cure properly causing the cracking. Another situation is where something like a hair spray had gotten on the wall causing the cracking.
Exterior, the cause in my experience, has been too many coats of paint or too much paint put on and thus affecting the curing rate.
In any case, simply painting over the cracked finish will not achieve a good result. You will need to remove the problem coat(s) and repaint.