Call Transfer

Hi,
Has anything changed recently that may affect call transfers ?
Our office uses Linksys SPA ATAs. To transfer calls the users normally press R (recall) to get the new dialtone and transfer calls as this is much quicker than ## via the PBX. This week they have complained of getting '3 way' conversations between the caller and 2 extensions. Sometimes when the target extension doesnt answer, the 1st extension presses R and goes back to the caller , meanwhile the target extension keeps on ringing. If somebody then picks up the ringing extension they join in a 3 way conversation. Users swear the target extensions never continued ringing previously, and I know nothing has changed on our router, internal network or ATAs. Weird or what !

Regards