Symptom:
one session without any number and offhook softkey layout will be viewed here,

Conditions:
Scene 1:
1. add one BLF SD  on phone A for phone B
2. press BLF SD on phone A , then phone B will be ringin, then end the call
3. let phone A for some days
4. press BLF SD again, ----------problem: one session without any number and offhook softkey layout will be viewed here, wait for 10~15s, call is dial out to phone B

scene 2:
1. add on BLF SD on phone A
2. make sure the BLF SD number is not existed on cucm, and no any pattern to match it
3. press BLF SD , -------problem: sometimes, one session without any number and offhook softkey layout will be viewed here, wait for a while, the recorder tone and correctl softkey layout will be viewed

 note: this problem hard to be reproduce