Q: What does a status change from "Under review" to "Evaluating recommendation" mean?

The status "Evaluating recommendation" indicates that the reviews for your paper are  complete and the Associate Editor (AE) is evaluating the reviewer suggestions to arrive at a decision about your paper.  The previous status is a little confusing though. I'm not sure if the "Under review" status refers to an external or an internal review. Generally speaking, the peer review process takes more than a month to complete, which makes me inclined to think that this was probably an internal review. If a paper moves from an internal review directly to "Evaluating recommendation," it is probably a case of desk rejection.

However, there is a possibility that the paper was sent for an external peer review (particularly since "Under review" appears twice) and that the reviewers were very prompt. The other possibility is that this is a rapid publication journal in which case it is not unusual for the peer review process to be completed within a month. Whatever it is, the current status makes it clear that the Associate Editor is now evaluating your paper to arrive at a decision.

However, note that the AE does not have the authority to make a final decision. He/she will give his/her recommendation to the Editor-in-chief who will take the final call on whether the paper will be rejected or accepted with major/minor changes. Once the AE has given his/her recommendation to the EiC, the status will change to "Decision in process." 

Related reading:

• How long does the status 'Evaluating Recommendation' take?
• What does a status change to 'Evaluating recommendation' from 'AE assigned, under review' mean?
• What does the status "Evaluation recommendation" mean?