Field disappear when i add two different fields in transform

Hi all, I am trying to use the transform in panel but it seems not working when I use two different fields. when I tried to use Binery operations on same field , grafana shows the field but as soon as I select other field, the output disappear.
I used STAT and Table both but same result. Grafana is working perfect when I am doing binery operations on 1 field (means add 1000 or subtract or divide or multiply) but as I select another field instead of number, the output disappear.

example info:
I am trying to do binary operations (add or divide) on this month_cost and customer_count but as soon as I Grafana is not displaying it. If I use same field then Grafana displays the result. I am currently using Grafana 7.2.0.

I was not able to reproduce your error on my test data. Is it possible that your calculation is resulting in something weird that Grafana can’t deal with?

I have 2 different datasources, one is Azure-Plus (which extract data from Azure, like cost) and one is SQL query (which retrieve the no of customers). when i try to do the operation on the outputs, field just disappear.
I tried to add a time field to do the join first (as Azure-Plus datasource retrieves cost plus date) but still it does not work.

what version are you using?