Seeing different results in Groovy 26.04 vs 26.05 in variable setting

Summary:

Validating business rules between 26.04 and 26.05 and we found syntax that produces different results

Content (please ensure you mask any confidential information):

We have a business rule that is producing different results in 26.04 than in 26.05. The portion of the rule that is giving different results is a line where we are setting the value of a substitution variable to a member that is retrieved out of a grid. The line in particular is:

String selPool = ([cell.getMemberName('Pool')])
println selPool

When this is run in 26.04 and prior, selPool comes back as (just showing an example):

POOL_100000

When this is run in 26.05, selPool comes back as: