I have now used decodepsbt to output the files in a readable JSON format. And what a difference!

I have to say that I basically did the same thing for both transactions from the user's point of view.

First, I transferred the entire credit balance from address 1 to address 2. First transaction. Then I transferred this credit from address 2 to address 3. Second transaction.

In the second transaction, I see an input and an output under non_witness_utxo. Mine.  I don't know what that means but it seems normal.

But with the first transaction, all kinds of other transactions appear under non_witness_utxo. There are amounts that my transaction has nothing to do with. My vout also appears there, of course, but so do many others.

Is there any way to prevent this? And how big can it get? Is there any limit? I need a new QR code every 2500 bytes. I therefore had to work with two QR codes for the first transaction.