Some of my groups have not received a welcome letter to mewa.io. Is this normal?

Welcome letters aren't sent automatically by mewa.io until there's an event like a termination. At that point, we'll send a welcome letter if they haven't already received one. This is just so that we're introducing the program at the time of need, rather than potentially sending a welcome letter to a program they may not interact with for months, at which point they may have forgotten that they received the welcome email in the first place.