My job deals with freelance writers for PR; I edit/oversee the content that they provide and often give feedback to them. I always try to keep a positive tone and thank them even if the main purpose of the email is to address a mistake. This kind of feedback is company policy and I have been instructed by my manager/senior colleagues to send it, especially to freelancers who are new to us.
We have a new experienced freelancer who I thought was very receptive to these emails, so I made an effort to contact him fairly regularly with feedback (mostly positive). Recently, I sent him an email regarding minor changes made in accordance with the end-client's preferences as I have done in the past, and received a very odd response that seemed to imply that this person was offended with the changes made.
I do not want to inadvertently damage my firm's relationship with this person, or other freelance workers, by making them feel undervalued or over-criticized. But at the same time, I do occasionally need to send them feedback or inform them of changes. Ideally I would be able to inform them of this prior to end-client delivery so they could have more input, but this is not possible as deadlines are often very tight.
Is there a better way to maintain positive relationships with freelance workers, particularly senior/experienced ones, without offending them over feedback?
(I found this answer How can I give feedback without hurting the other person? but I don't think it is relevant in this case as it largely refers to personal comments.)