SYMPTOM
When exporting dashboard visualization to excel of a report containing a blank value when adding a formula expression to the cell users may notice a #VAULE message being returned.
STEPS TO REPRODUCE
Found in 10.4 HotFix 7:
1. Create a data set with at least one blank value as shown below:

2. Export the visulasation to excel from 10.4 HF7
3. Try adding a formula to the blank value notice the #VALUE is returned

CAUSE
This change in behavior was brought by alteration in the new export engine. Below it is shown the issue is not encountered when exporting the same visulasation to excel with Strategy 10.4 no hotfix

ACTION
Currently this issue is being reviewed by Strategy for a potential code fix on an upcoming Strategy release. KB441095