Counting number of options in a multiselect custom field

Hi @Marcelo_Ignacio_Cid1,

If “Block” is already a specific issue type for sub-tasks, then this information is already available in eayzBI. Check the “Issue Type” dimension.

In the report, use the “Issue” dimension Sub-task hierarchy on report rows and measure “Issue created” showing how many subtasks and issue itself are created for each row.

To get sub-task count by issue type (including sub-taks issue type), click on measure “Issues created” and chose the option Drill into >> Issue Type >> Issue Type (see documentation Create reports - Drill into measure by another dimension level).
Then you can adjust which issue types you would like to see on report columns:

Or you may create a calculated measure using tuple expression as described in this community post:

([Measures].[Issues created],
[Issue Type].[Block])