That time Jobs::GenerateEmbeddings is expected to take seconds a hit, cause you are making an API call to an embedding service to get the data. That graph is normal, it just shows something it taking a while, another GPU in the cloud is actually doing the work.
CPU going high is very unexpected, maybe your PG setup started extremely resource strained and inserting 1000 or so numbers in a row is enough to hurt it.
We need a lot more data here to help diagnose, what are the specs on the server? What are actual CPU graphs showing, which process is consuming CPU, what embedding service are you using, etc…