Basically, it's a built in feature of mod_sofia for FreeSWITCH that doesn't appear to have anyway of disabling (if I recall, I haven't researched the source in a while). If the call is completed elsewhere, FreeSWITCH will send the reason 'Call Completed Elsewhere' and your phone will be programmed to not treat this as a missed call.
Short answer: No
Long Answer: Your options are:
1. Ask on the SignalWire forums, though they can be quite dismissive at times.
2. See if your phones have a configuration setting to treat those calls as missed calls.