Null values Records are not showing in Powerbi Visualization.

Having the Null values in the Dataset, but when doing the basic filtering by selecting the Blank check box the count is showing but in visualization the null values are not showing.

Requirement : 
we have three tables "Table A", "Table B" and one "LookupDomain  Table". Here in the Table B null values be there, first we have to check for null values,  if is having null values , the null values should be replace with the Table A values, if Table B is having a value, the same has to be shown. 
For that created a Dax Measure, this formula is working as Expected, 
Measure_TEST =
var earlyClassificationID = SELECTEDVALUE(TABLE_A[ID])
var earlyClassificationNum = LOOKUPVALUE(LOOKUP_TABLE[Number],LOOKUP_TABLE[Id],earlyClassificationID)
var finalClassificationNum = SELECTEDVALUE(TABLE_B[Value])
var resultClassificationID = COALESCE(finalClassificationNum,earlyClassificationNum)
var resultClassDesc = LOOKUPVALUE(LOOKUP_TABLE[Description],LOOKUP_TABLE[Number],resultClassificationID)
return resultClassDesc.

Issue :
Blank Records data is not visible in the visualization : 

1. The Null entries are there in the dataset, but when performing the basic filtering in the visualization filter to check the Null records data , It is completely blank and no records are showing.
2. After that added  that  one column of this measure  in visualization, after that checked the basic filtering by selecting the Blank values , the blank records are not showing.
3. Next approach i tried by removing that created measure column in visualization, then did same approach checked the basic filtering by selecting the Blank values , the blank records are  showing.

4. Expect for blank, for all the values if we do filter it is showing the data in the visualization.
5. No filters were applied in the Visualization.

What is the issue not sure, any issue with this measure? how come this measure causing the issue?
Can someone provide thesome insights, need help .