An unnamed source from Larian answered WCCFTech, "When multiclassing, the levels of your classes and subclasses that normally have access to spell slots are added together in a weighted formula, and then the overall spellcasting level is used to determine how many and which levels of spell slots you will receive. Warlocks are an exception here in that they only get their fixed-level spell slots."
https://wccftech.com/baldurs-gate-3...racters-rule-changes-crossplay-and-more/I don't know if WCCFTech is a reliable source or if they actually contacted Larian as stated in the article. First "official" clarification that I've seen. Guess we'll find out what it means in a few days.
