Google posted on the data anomalies page under the search analytics section that the data for the job posting report may differ after May 29, 2018 because it is now pulling from Web Light search results.
May 29 onward:
Job posting data is now being collected from Web Light search results. Because of this, you might see an increase in your clicks and impressions for job postings.
So if you notice a change in your job posting data specifically seeing an increase in your clicks and impressions around that markup, you are not alone. It is just that Google has changed how they look at that information.
It is super interesting that Google would use the Web Light search results for this, isn’t it?
Forum discussion at Twitter.