Problem with updating Managed Metadata column along with other column types to drive item in sharepoint using Graph API c#

Im experiencing a situation where when i try to update metadata to a driveitem using graph api, it doesnt update all the fields i tell it to.

this is the field additional data column im trying to work with.

fieldvalueset = new FieldValueSet
                    {
                        AdditionalData = new Dictionary<string, object>()
                                    {
                                        {"aeaaa8de8b8c4df99f251ec41b221cb5",termreferences},
                                        {"c9e01cf2707746118721ab0ba03d23a7", directortermreferences},
                                        {"fec9fa55dcc34d41a5eae8927e5fb90d",SectionTermRef },
                                        {"Document_x0020_Type","BTOR" },
                                        {"Prepared_x0020_ByLookupId",userLookupId },
                                        {"State","Draft" }
                                    }
                    };

now the first three are metadata lookup fields and the termreference are in the required format to deal with those types of metadata.

1.termreference is a multiselect lookup
2.directoratetermreference is a single lookup
3.sectiontermref is a single lookup
4.document_x0020_type is a choice option
5.prepared_x0020_bylookupid is a person and group type
6.state is a choice option

what im experiencing is very strange.

1. when i populate columns 1,4,5,6 they all populate correctly.
2. when i try to populate all at once, only the termreferences ( 1,2,3 ) populate , all the others are left blank
3. when i try to populate 2,4,5,6 only 2 is populated

for some reason when i try to populate the single lookups to term references, they somehow erase the non-lookup metadata from the file.

the update code i have is

var updatefield= await graph
                      .Sites[siteId]
                      .Drives[DriveId]
                      .Items[Driveitem.Id]
                      .ListItem
                      .Fields
                      .Request()
                      .UpdateAsync(fieldvalueset);

this is the format of the term references

//for single termreference 
termreferences = "-1;#" + term.Label + "|" + term.TermGuid;

//within a loop for multichoice term reference
 if(termreferences=="")
                        {
                            termreferences = "-1;#" + term.Label + "|" + term.TermGuid;
                        }
                        else
                        {
                            termreferences= termreferences+";#"+ "-1;#" + term.Label + "|" + term.TermGuid;
                        }

Iv tried everything and cant seem to figure out why its removing the non term fields.
I even tried updating the term fields first then the other after, but there doesnt seem to be an append function. UpdateAsync removes previous metadata when you do another call to it.

anyone know the workaround to this ?

Seems to be a problem with populating the Single managed metadata fields with other metadata.

Converted the single input fields to multi-input and they worked fine along with the other metadata tags.

Solved my immediate problem, but was not able to identify what the problem was with single input managed metadata updating.