Bailey what's up? ... I see this color break on seedlings fairly often here,... never found a definite reason or cause, and usually it goes away on newer leaves; as far as I can tell, it's not nutrient related, or bugs, even medium pH related; nute splash-burn is very rare, typically with overly strong nutes and direct intense lighting (or Sun), and even then it's uncommon; on a seedling with reduced light intensity, even more rare,... foliar feeding is a very common practice across the whole horticultural industry, including cannabis... So all the arm-flapping about splashes is greatly exaggerated!
...that said, this "general" symptom can occur with viral infected plants as part of other co-symptoms, which I don't see here at all, and it's super super rare, so don't sweat it! If it was worse, persistent with most if not all leaves, with deformations, then there'd be some concern!