ok I was suggested the following UPDATE statement and it seems to work...
update cmn_list_of_values
set object_code = ''
where lookup_source_code = 'LOOKUP_SOURCE_DYNAMIC'
AND lookup_type_code = 'BROWSE_PROJMGR'
obviously that would be unsupported I assume any other alternative? I am working on a Test environment therefore I hope it won't be too harmful...