The answer would be to stop editing, but without your code, the specifics are unclear here.
If you were manually editing the table before, save or discard those edits and try again.
Elsewise, if you have an editor object Editor—ArcGIS Pro | Documentation, try removing it or placing the truncate outside of the edit loop if structured as
with arcpy.da.Editor(workspace) as edit:
If neither of these work, post your code and we can figure it out.