Issues with sending messages on primary and secondary lines

I have two lines on my iPhone 13 (personal and business). I set default lines to use for each contact. Recently, when I send a text message to a client that already has the default line set up to my business line, it sends from my personal line. Even when I make sure that it has the business line selected, it reverts back to the personal line. I don’t have this problem with phone calls, just text messages. This is extremely frustrating because some of my clients recognize this new number and don’t respond to me.