Autocorrect whole words only?

Being a lousy typist I make a lot of mistakes and love autocorrect. However, there’s a minor problem with Scrivener’s implementation (v.3, beta 18), which is that if an error occurs as part of a longer word, it gets corrected when the longer word is already correct.

Specific example: I often type “thier” for “their”, so that’s an autocorrect entry. However, when I try to type “healthier”, Scrivener changes it to “healtheir” everytime. I tried adding a second autocorrect (healtheir to healthier), but that didn’t work, even though I placed it lower down the list (see screenshot).

This doesn’t happen in Ms Word, so I’m assuming it has some way of “knowing” that corrections apply only to whole words. Any chance of a similar feature in some future (3.x) version of Scrivener?