Name for misused idioms

Solution 1:

When someone uses the wrong word, especially one that sounds like the right word, that's called a malapropism. I'm fairly sure that works for wrong sequences of words too.

Solution 2:

I'd say you're coming across some mixed metaphors:

Mixed Metaphor: An overreaching or contradictory combination of two distinct metaphors, similes or idioms.

Example: "They’re diabolically opposed

With maybe a few eggcorns:

Eggcorn: an idiosyncratic substitution of a word or phrase for a word or words that sound similar or identical in the speaker's dialect. The new phrase introduces a meaning that is different from the original but plausible in the same context.

Example: "old-timers'disease" for "Alzheimer's disease".2

Eggcorns are different than malapropisms because Eggcorns sound plausible, whereas malapropisms create nonsense phrases.

We know what the writer means and it's correct in context, yet the idiom just doesn't seem quite right, maybe due to nuances that someone has overlooked, or perhaps, in their haste, someone chose the wrong expression.