You need to distinguish between PIP and ESA/UC telephone assessments - the guidance is different for each.
ESA/UC Work Capability Assessments by telephone are still being done for those with MH issues.
There is special guidance for HCPs doing telephone WCAs which covers claimants with MH conditions.
I'm not sure what the guidance is with PIP telephone assessments.
The lastest assessors guidance I have for telephone WCAs (for ESA/UC LCWRA) can be found here:
Telephone WCA clerical (report form) guidance. - August 2020