Managed metadata showing up randomly in lists (might be PnP Provisioning related)

Dear people,

I have SharePoint sites with a lot of lists each containing a couple of managed metadata columns. The sites are defined in a template and get rolled out via PnP provisioning. I did that many times before and never had this:

The lists show a weird behavior: some items get randomly the value of a specific managed metadata (it's always the same). None of the columns have set a default value. All lists have only list content types - no site content types. The lists where the metadata shows up don't even have a column where this metadata is set.

I was suspecting the -1 setting in the default value in the columns to connect to the Hidden Taxonomy List so I removed all default values. But the issue persists.

Has anyone ever experienced this?

Thank y'all!