Compression - honoring "q" weight values in Accept-Encoding header

Interesting. Perhaps the F5 simply ignores the q values. Have you tried changing the compression setting to deflate on the F5 (and reversing the q values) to see if that changes what's used? If so, you can confidently assume the F5 is ignoring q values.

Regarding your second request, I think

*;q=0

effectively means you will only accept an encoded version (which may or may not be compressed). I think to disable compression you would need

identity;q=1 *;q=o

for disable compression. Of course, if the F5 is ignoring q values a value of

identity

alone may be your only option.