Reference method switching: Default to other

Same here, ECA destroys the selected reference method and therefore the configuration for the field upon saving. This is a major issue at the moment in our projects.

But: this issue is not related to the taxonomy manager. I am facing the same issue with taxonomy manger uninstalled. I guess this is a core issue, where other reference methods get selected when the currently chosen reference method is "default" in the database. This seems to be a selection issue of the default value in the widget.

Placed it as core issue:

https://www.drupal.org/project/drupal/issues/3481711 🐛 Reference method of reference field switches to first available in list if previously set to default Active

It is really interesting. ECA does not affect my project structure.Even if I uninstall ECA, it does not change, the problem persists.
I still haven't figured out what the main factor is.
Let me give you another example.
For example, let's say Dependent Fields and Taxonomy manager modules are active. This time, instead of ECA option, the "Make field dependent using views" option, which comes as an option of the Dependent Fields module, is selected.
However, when I uninstall Taxonomy Manager, the problem goes away.
As you said, maybe it is a core issue. Thanks for support.

If anyone is experiencing this problem and only needs to import terms, try this module as a temporary alternative solution.
The way it works is similar to Taxonomy Manager. There is also a bulk delete function. Taxonomy Fast Import →