I’m experiencing similar behaviour with a newly deployed gatsby build. I’m seeing some assets take the same (long) time to load. For example there are 6 files (a few js files from the gatsby build, a webpack js file and a page-data json file) that all take exactly 33.41 seconds to load, another batch of 4 similar files all take 25.19 seconds. This is all the case when checking on wifi, checking on a cellular 4g network the performance is normal/as expected.
Hoping to find our some more information if possible