Browser fails to cache SWF file

Question

I am having an issue with the browser not caching a SWF file.

I have the following in my apache configuration:

 ExpiresByType application/x-shockwave-flash "access plus 2 months"

I can see the headers coming back from the original request for the SWF look like this (the expires header looks like it's being set properly):

Request:

User-Agent  Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5
Accept  HTTP Accept=text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding gzip,deflate
Cookie  auth_token=

Response:

Server  Apache/2.2.8 (Ubuntu) PHP/5.2.4-2ubuntu5.5 with Suhosin-Patch proxy_html/3.0.0 mod_ssl/2.2.8 OpenSSL/0.9.8g Phusion_Passenger/2.2.5
Last-Modified   Sat, 14 Nov 2009 04:48:19 GMT
Etag    "49384-4784d7c3c8ac0"
Accept-Ranges   bytes
Content-Length  299908
Cache-Control   max-age=5184000
Expires Fri, 15 Jan 2010 20:25:42 GMT
Content-Type    application/x-shockwave-flash

However, on subsequent loads of the page, the browser still sends If-Range requests for the SWF as follows:

Request:

User-Agent  Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.1.5) Gecko/20091102 Firefox/3.5.5
Accept  HTTP Accept=text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding gzip,deflate
Cookie   auth_token=
Range   bytes=0-
If-Range    "49384-4784d7c3c8ac0"

Response:

Server  Apache/2.2.8 (Ubuntu) PHP/5.2.4-2ubuntu5.5 with Suhosin-Patch proxy_html/3.0.0 mod_ssl/2.2.8 OpenSSL/0.9.8g Phusion_Passenger/2.2.5
Last-Modified   Sat, 14 Nov 2009 04:48:19 GMT
Etag    "49384-4784d7c3c8ac0"
Accept-Ranges   bytes
Content-Length  299908
Cache-Control   max-age=5184000
Expires Fri, 15 Jan 2010 20:25:45 GMT
Content-Range   bytes 0-299907/299908
Content-Type    application/x-shockwave-flash

These subsequent requests appear to be sending the Etag in the If-Range header, and are getting 206 responses with the entire content. I've tried setting apache up to unset the Accept-Ranges header and Etags, but the browser will re-request the file in either cases.

Has anyone seen anything like this before and know what to do to get the SWF to cache?

Thanks!