Something seems to be broken in the setup of my online accounts: whenever I get transactions for one of my accounts (via HBCI), Gnucash creates transactions for a different account and also looks for transactions to match in that other account.
I would assume the problem is that I've matched the accounts wrong, but first I've quadruple-checked that the online account is associated with the correct Gnucash account and second, if it weren't, then Gnucash wouldn't even offer the option to "Get transactions" for that account in "Online Transactions."
At some point, I did have the online account associated with the wrong Gnucash account and I suspect that Gnucash simply doesn't update that setting correctly. But it doesn't show this faulty association anywhere I can see.
My question is: how does Gnucash decide for which account to create transactions when importing, and how do I change that?