SPA502G: on-call sometimes the "xfer" soft-button p and teh CONF soft-button displays in the middle. Help

[peter00073]

We deployed 100+ SPA502G/SPA504G phones. Some users have problems with the soft-buttons:

On call the "xfer" button disappears and only a  "Conf"  soft-button is showing in the middle of the display. Users can't transfer a call anymore.

This happens now and then. What's could be the problem?

Firmware 7.5.6

[Julien Berthelot]

We were on version 7.5.5 (not b) and never had this issue. 

I upgraded about 300 phones to 7.5.6 this weekend and we started to see this issue also.

[peter00073]

We went back to firmware 7.5.5b and the problem was gone. We hope Cisco comes with a update soon because some vulnerabilities where fixed in 7.5.6.

[FlyingDoctor_2]

Xfer and Bxfer buttons now not show in 7.5.6. if receiving an anonymous call

[Dan Lukes]

Note XferLX, how should this work?