Decomposition tree Bug: + button showing up on lines for the collapsed view (since 3rd week of May)

The decomposition tree visual (published in the service) was working fine till 2nd week of May 2022. But since

Since last week it shows with the first level expanded (and no way to cancel that as the header for the field is also missing!). And the + button shows up on the lines where they are to split up (see below image).

Note: The visual was not expanded by default (i would let the user expand this visual). But now i see it expanded to one level by default.