Edits seem to be grouped into changesets incorrectly
I'm submitting a bug report
Brief Description
Edits done on the same object are grouped into one changeset in the display, even if these changes have been done in different changesets.
What is the current behaviour?
Let's look at changeset 56188366:
According to Osm Changeset Analyzer, the user added four tags on the Heidbusch road in that changeset:

However, looking at the history of the element in JOSM, one can see that the four changes were actually uploaded in three different changesets (i.e. look at the changeset number I framed with a green rectangle in the screenshot)

The changeset on OpenStreetMap also lists only version 10 of the way as being part of the 56188366 changeset:

What is the expected behaviour?
The expected behavior would be that OsmCha only shows the changes that really belong to the changeset that is currently shown
Other Information / context:
This bug was initially reported at https://github.com/westnordost/StreetComplete/issues/853 but it turned out it is only not displayed correctly.
Also reported as #492