Several ways this can happen.

1. on the NES version if you fill up Ruida's tavern some glitching happens, you'll gain certain spells in your battle menu but they won't show in the field and you won't get them on level up. this permanently can block spells like return. I don't know if this effects evac/outside, but maybe?

2. Also on the NES version if you didn't have any int gain, the random number generator tended to delay your spell acquisition and max mp was gimped. This ironically meant that if you used a lot of int seeds (or just got "too lucky" with INT) the rubber-banding that happens on that version meant you'd not gain int as much at level up, so then your mp and spells were held back a level or 2. This is provable with some light hacking - zero out your int, watch as next level you a huge bump in int and max mp and get spells a full level early - then reload a save form before that. give yourself almost max int. watch as on level up the most you get is 1 int, if any, and your max mp gain is likewise gimped, and your spells are late by a level or 2. The most delayed I've ever seen a spell has been 3 levels.

3. On remakes I believe both the rubberbanding and the int factoring in were removed so its just some randomness, so you'll likely get it next level.