proxypass not changing response header properly

I am using proxypass for reverse proxy functionality and it is working fine except for one site. This site responds to the client with a new http header as follows

 

 

 

Changing response header Location: index.cfm?CFID=6069&CFTOKEN=83747944 with index.cfm?CFID=6069&CFTOKEN=83747944host.outside.com/atms

 

 

 

It is not adding in the required & between the end of the token and the host name. the header should be changed to:

 

 

index.cfm?CFID=6069&CFTOKEN=83747944&host.outside.com/atms

 

 

 

 

Any idea why it is doing the responses correctly for all the other sites running through proxypass but for this one it is not including the &

 

 

Without the & to differentiate the token from the host it goes straight to an error page.