Yes, and its not a bug.
The PHB says that wizards can learn any spell from scrolls they have spell slots for.
And in D&D5 you can gain higher level spell slots through multiclassing.
So there is nothing to "fix".
I don't actually think it needs to be fixed, but any time I try explaining to people that a multiclassed Wizard using this trick is still weaker than a pure sorcerer they just stay mad and continue to view it as an exploit.
All the memorizable utility spells? Druids can cast them all without needing to memorize scrolls. Damage spells? You pick fire or lightning and just upcast fireball or lightning bolt. Lightning is better as theres several subclasses that boost lightning spells, and also you get chain lightning with your level 6 slots.
Theres no spells I absolutely needed to memorize, just that at first deep into act 3 I was struggling to find a lightning bolt scroll to try out the multiclass lightning spec, and its ok but still not as good as a pure sorcerer. The level 1 ritual spells like featherfall / enhance leap and such, you can pick them on an EK or AT if you really want them - Laezel with athletics and enhance leap basically jumps across the the entire map. For longstrider make a camp transmutation wizard, or have either halsim or jaheira pre buff from camp.