[NewsAware]

If this is a small company, I would probably not worry too much about process and ask the concerned employee to discuss this in a friendly and open way. Maybe a misunderstanding which can be cleared, maybe the reason is actually lying deeper. Good chance you can resolve this by being emphatic and act understandingly.

That being said, I would note down a memory protocol afterwards in case this turns ugly after all.

[dvanwag]

I'm not sure what you mean by a memory protocol, what is that?

[Spooky23]

Sometimes they are called memorandum for the record.

Send yourself an email with your recollection of the incident and print a copy that you do not keep at work. If there is a problem later, you’ll have documentation of your contemporaneous thoughts that can be used to corroborate yourself.

It’s good practice whenever something significant happens.

[jason_slack]

Perhaps OP means to jot down some notes, with dates and times to remember what happened and when should this arise again.