MY problem is my exposure to this particular issue is very limited AND over my head. Let me share with you my frustration.
I found a two relay module in my collection.Perfect I say, let me try to latch one according to your ...schematic.
Both relays have one 5 volt source and ground. Did that
The module has a "weared" jumper ( 3 pins labeled JD-VCC, VCC, and Ground) Have no clue for their purpose.
The default came with pin 1 and 2 has a jumper again no clue)
The triggers labelled IN2 and IN2.
Tried to apply 5 volt to IN1 or IN2 nothing.....Applied zero volt the Relay 1 and Relay 2 worked.
So, this module activate on LOW.
So far, so good.
According to your schematic you connected 5 V to the NO pin of Relay one. My understanding is you did it, to latch relay 2. I hope I am correct !!!
Then the frustration starts: I want to latch relay 2. so applied 0 volt to IN1 and IN2
My expectation is that both relays will activate AND RELAY 2 remain LATCHED after the trigger..... no way
I am definitely doing something wrong but WHAT ???.... I hope the "quality of my questions" matches your expectation.