Shaikh Abdullāh Al-Bukhārī, may Allāh protect him from every kind of harm, said:
So not everyone against whom a refutation has been made is considered–what?–an innovator. And not everyone who has been warned against is an innovator.
Similarly, it is not the case that everyone who has not been refuted is a Sunnī. And it is not the case that everyone against whom a warning has been withheld is a Sunnī.
For indeed, one who has been refuted may be a Sunnī, and he may be an innovator. And one who has been warned against may be an innovator, and he may be a Sunnī–he has an inability [this Sunnī] to make good decisions, he has rashness, he has hastiness; he is not suitable, is not qualified. So he is warned against due to his poor character, his poor ability to make decisions, his rashness, his not being qualified–do you understand?–and [for] the like of that.
So the issuance of a warning [against someone] is not a proof of [his being upon] innovation. And there being silence [and no warning against a person] is not a proof of [his] being upon the Sunnah.
N.B. Italics mine. (Trans.)
Source: From “The Rule with Regard to Having Patience with the Mistakes Made by a Salafi.” http://elbukhari.com/wp-content/uploads/2016/01/fawaid_sawtiyah_sh_albukhary_102.mp3. (6:29 – 7:31).