Adobe Campaign Classic - add/remove activities which change temporary schema

Hello,

I'm struggling with the following issue: i added the activity to call subworkflow in a live workflow, and this caused an error since (i think) the following union activity were based on a different temporary schema. I think this occurs every time i add/remove an activity that change temporary schema (e.g. enrichment/change dimension).

Do you know if it exists a workaround?

Maybe i could replace the following activities that cause the error (e.g. union in my case), but then i could face the same problem with activities after this union.

Thank you in advance