Other (related) nodes with the same taxonomy block grouping problem
I've used tags as the term field, so adjust for that.

Create the block view as follows:

A view of content (nodes).

Relationships:


Content: Tags (field_tags), require relationship  // you will use your term field here
Taxonomy term: Content using Tags (Relate each Content with a Tags set to the term.) and set the relationship to the first relationship added, and tick require this relationship // yours will be named differently


Contextual filters:


Content: Nid (node id). Set the relationship to the second relationship added. Provide a default value of Content ID from URL for WHEN THE FILTER VALUE IS NOT AVAILABLE. Specify a validation criteria of Content -> your content type -> Node ID -> Hide view
Content: Nid (node ID). DO NOT USE A RELATIONSHIP. Provide a default value of Content ID from URL for WHEN THE FILTER VALUE IS NOT AVAILABLE. Specify a validation criteria of Content -> your content type -> Node ID -> Hide view. Click on more and tick Exclude.


Fields:


Content Title (NO relationship)
Taxonomy term: Name, use relationship 1, and hide from display


Sort Criteria


Taxonomy term: Name, use relationship 1, ascending
Content Title, ascending


Filter Criteria

Add a filter of Content (node) type to filter on your content type.

Format:

Unformatted list, with settings: Grouping field Nr.1 set to the term field (field 2)