Feedback that shows up a month late is just a history lesson. Say it while it can still help.

Information arrives as help or it arrives as a verdict, and timing decides which. A month later there is nothing the person can do with it except feel bad, and they will reasonably wonder why you watched it happen four more times without saying anything. Speed is most of what makes correction feel useful rather than like judgement.

If something is bothering you about how a job is being done, say it within a day or two while it can still change the next attempt. Keep it to the one thing. Saved-up feedback is a pile, and nobody can act on a pile.