If you just replaced the existing switch with the momentary Legrand, then the switch you modified is working correctly. It’s a momentary pushbutton so it won’t keep the lights on until it’s connected to an aeon module which has a configuration option to work with momentary switches.
The second switch gets modified just like the first one.
Here’s the way I wired mine up with pushbuttons.
You also need to change the aeon parameters to momentary, this can be done in the preferences section using these custom device types. After changing the parameters you can switch back to the stock ST device type if you want.