I've got the very same thing! Almoste burn my mind trying to uderstand GZip compression issue!
Chrome Dev Tools didnt show Gzip
If I send browser User-Agent Curl also didnt show GZip.
Also I tried to disable ESET but it make no changes. Gzip didn't show up.
Only Wireshark shows that server responds with GZip.
Althought I didn't really sure it is ESET. But its very possible reason.
Can support clearify that?
Thanks in advance.