Can you post the code you are using? Here is an example of editing a versioned feature class:
import arcpy
import os
fc = 'Database Connections/VECTOR@SQLSERVER.sde/AddressPts'
workspace = os.path.dirname(fc)
# Start an edit session. Must provide the worksapce.
edit = arcpy.da.Editor(workspace)
# Edit session is started without an undo/redo stack for versioned data
# (for second argument, use False for unversioned data)
edit.startEditing(False, True)
# Start an edit operation
edit.startOperation()
# Insert a row into the table.
with arcpy.da.InsertCursor(fc, ('SHAPE@', 'Address')) as icur:
icur.insertRow([(601181.055124, 762555.994028), '120 Main St'])
# Stop the edit operation.
edit.stopOperation()
# Stop the edit session and save the changes
edit.stopEditing(True)