I have been experiencing slower let down in the evenings. I know my supply has been up and down due to working. But for the last three or four nights my 4 mo old has tried to nurse at her last feeding, gets frustrated, cries, and then as a last resort will take 2-3 oz. of ebm from a bottle (slow flow nipple).
Obviously, I'd rather nurse her.
She also has been falling asleep and waking up 2 hours later to nurse.
She will nurse all night long in her sleep and fine in the morning - just the evening time is tricky.