Playing in VH difficulty and 1.30.4, I saw none of the big powers (France, England, Commonwealth, Russia, Ottomans, Ming and so on, I am Spain) having debt issues. The AI is taking debts for institutions but is able to pay them back. I (Spain) is allied to Ottomans and Ming and 90% of the time they won't have debts reducing their chances to go to war with me. Same for my enemies, very rarely did they not answer a CtA due to debt issues. Even my CNs have no big debts !afaik the debt spiral isnt fixed yet. So if you wanna roflstomp all over europe, it´s gonna be fun, if you want to have a challenge, I´d rather play somewhere else
I remember that in 1.29, I was playing Grenada->Andalusia and was allied with the Ottomans for two centuries, I was only able to call them in an offensive war once, then they always had debts and even at the stage that they don't answer defensive CtA in the end.
So I don't know if it is fixed, but at least in this game I have not seen it.