Hello, we have live agent enabled in our org and 3 agents to answer the incoming chats. All of the 3 agents have the same profile.
When a agent receive a chat request through the 'prechat' page a Lead, a Person Account and a Case are created in SF.
The agents should then see the chat tab plus a another tab with the Lead and the chat details (transcript) (see screenshot 'correct'). At the end of the chat from the agent side a Transcript is created, with a linked Case and Lead.
Since Monday 13/02/2017 for two of our agents in the 'chat page' they see only the chat and chat details tab, not the Lead tab. At the end of the chat the Transcript is saved but it isn't linked to any other Case nor Lead.
We saw that all of this is cause at the start of the chat the Lead isn't created anymore.

We tried to analyze the debug logs but when the error appears this is the only thing recorded:
Operation: /liveagent/chatrecordstab.apexp
39.0 APEX_CODE,DEBUG;APEX_PROFILING,INFO;CALLOUT,INFO;DB,INFO;SYSTEM,INFO;VALIDATION,INFO;VISUALFORCE,INFO;WAVE,FINEST;WORKFLOW,INFO
14:55:27.0 (70021)|USER_INFO|[EXTERNAL]|00520000005fyEB|officer5enitfres@gmail.com|Heure d'Europe centrale|GMT+01:00
14:55:27.0 (100697)|EXECUTION_STARTED
14:55:27.0 (106197)|CODE_UNIT_STARTED|[EXTERNAL]|VisualForce View State
14:55:27.0 (4491898)|CODE_UNIT_FINISHED|VisualForce View State
14:55:27.0 (5345702)|EXECUTION_FINISHED

In the last month or more we didn't modify anything about Live Agent or about the Profile of the Agents. We also can't comprehend how is it possible that 2/3 of our agents are having problems and the other one have no problems at all.

Is it possible that during the Spring '17 there were changes that disrupted our Live Agent implementation? What can we do to track down the error and fix it?
Thank you in advance
Maria Alberti