[Bug]: gzip encoding is not consistent

### Problem description

gzip compression seems random. Some files are sometimes served un-gzipped when they should, based on https://docs.deno.com/deploy/api/compression

### Steps to reproduce

- go to https://fresh.deno.dev/
- In devTools, disable cache.
- check network tab, note the number of js files being served gzipped. (filter by js file and sort by name for ease of comparison)

- refresh site and check again

- repeat as needed.

It is not always the same set of files being served gzipped.

### Expected behavior

I expect the behavior to be consistent with the documentation. i.e gzip is applied consistently.

### Environment

It seems to only affect deno deploy. I cannot reproduce on deno v1.42.0.

### Possible solution

_No response_

### Additional context

_No response_