QGIS version 3.4.2.2
Freehand version - Freehand Editing 3 v1.1.0
At the time of writing these are the latest versions for both.
I have a layer which has 'Hide form on add feature' set on the Attributes Form tab of layer settings
When using the vanilla tools to add a polygon, no there is no pop-up, however when using Freehand, the attributes form still pops up
I've then also checked 'suppress attribute form on add feature' in the programme settings, but this gives the same results as above.