Okay, you know I'm not much of a prescriptivist when it comes to English style. But the nuts and bolts of grammar? Yes, it is possible to get those wrong.
But please don't really on a grammar checker for your pointers.
Take this sentence:
Mr X. proved himself able to handle a variety of topics at ILR Level 3.The grammar checker would like me to get rid of himself and replace it with ... he. WTF? Oh, okay. If I do that, it immediately tells me that I should use him instead. Why can't it just say that in the first place? But I digress...
In its "explanation" it says
Use pronouns ending in "self" in conjunction with a noun, as in "Andrew himself" or when the pronoun refers back to the subject, as in "I hit myself." Use "own" in conjunction with a pronoun only when referring back to the subject.Okay. Fine. (Well, except for the missing comma after "Andrew himself".) All well and good. (Of course, in my sentence "himself" does refer back to the subject.) But then it gives these two examples.
Instead of: They heard herself on the radio.Neither of those seems anything that anyone would write (well, possibly in some dialects with a capital H for that first one). And neither is anything like mine. Why doesn't it try and show the difference between
Consider: They heard her on the radio.
Instead of: John watched her own meal get cold.
Consider: John watched her meal get cold.
They heard themselves on the radio.Sure, it'd need a few more words, but that's the kind of advice people need. Though, come to think of it, it didn't ask me if "Mr X. proved him able to handle a variety of topics" was perhaps incorrect. Maybe it doesn't know.
They heard them on the radio.
John watched his own meal get cold.
John watched his meal get cold.
Maybe it just has a simple prompt triggered by the appearance of the -self morpheme?
Pfft. Of course that's all it has. That's why you shouldn't pay it much (if indeed) any mind.