Did you get this solved? I have a custom taxonomy with several ACF attached to it. For some reason one of the fields, a WYSIWIG never shows up using get_field, and only ever shows null if I printr it. I have deactivated all plugins but nothing I have tried makes it display.
I actually solved my problem with WYSIWIG ACF not showing up on taxonomy with this code – basically having to pass the taxonomy and post id in the get_field parameter. This only seems to be necessary on the WYSIWIG field, all other field display with out this.