I would add my 2 cents. The problem is more global and affects any caster multiclass that has a small number of Warlock levels. Having 1 level in the Warlock class and 1 level in the Sorcerer class (spell slots of the same level - 1) I cannot use Warlock spell slots for sorcerer spells and vice versa. Starting at 3rd level sorcerer (W - 1, S - 3) when gaining 2nd level sorcerer spell slots, Warlock (1st level) spell slots will only be used when burning all 1st level sorcerer spell slots (including generating sorcery points), at this time Warlock spells will consume sorcerer level 2 spell slots, and the higher level sorcerer spell slots are available, the higher the level will be spent to cast a Warlock spell.
