1 unit displays red line to the left and Blind transfer soft key has disappeared.
welcome to the Polycom Community.
It is always useful to include the currently used UC Software version as issues experienced or a question asked may already be addressed in a newer release.
Please also include if you are using a SIP server or a LYNC / Skype for Business server.
If LYNC or Skype please provide Version details and if these are on premise of off premise
This also allows yourself and others to check against current software release notes, Administrator Guides or FAQ post’s.
The above is also stated in the "Read First"
Therefore the Polycom VoIP FAQ contains this post here:
Question: How can I find out my SIP or UC Software Version of my Phone?
Resolution: Please check here
In regards of the Blind transfer that may just be configuration so please supply a backup.
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
Polycom Global Services
Very sorry, I thought I had included this;
Plateform: Ring Central