Azure Logic Apps Workflow Templates (Preview): Issues with Updates, Expressions, and Designer UI.

Good report—these look like two product issues plus one documented designer behavior.

For the name, Microsoft’s template documentation says the JSON workflow name can be renamed only once. If you’re changing it after setup, the failure may be expected; the Profile display name is separate. If the Profile name will not save, capture the correlation or activity ID and open an Azure support request.

For base64(...), the expression reference warns that Designer may hide the function and show only its argument. Check Code view after saving. If base64(...) remains in JSON, runtime behavior is preserved. Editing the argument in Designer can remove the function and its effect, so keep the workflow under source control and make the change through Code view or deployment until resolved.

The missing Add Expression control at smaller resolutions looks like a preview UI defect. Browser zoom is only a workaround. Report browser version, resolution, zoom, Logic App SKU and region, timestamp, and screenshots through Azure Portal > Help + support; Community Lounge is not the product support queue.

https://learn.microsoft.com/en-us/azure/logic-apps/expression-functions-reference#base64