Compare [[ https://en.wiktionary.org/wiki/ngumisi?useparsoid=1 | Parsoid ]] vs [[ https://en.wiktionary.org/wiki/ngumisi?useparsoid=0 | legacy ]], specifically the link "complete aspect of **ngumisi**". The HTML for Parsoid includes a full link whereas legacy output doesn't.
The output comes from templates, and it is likely that modules on enwiktionary are generating this output and their self-link checks are broken for Parsoid. https://en.wiktionary.org/wiki/Module:links#L-438--L-451 is a likely culprit that needs closer investiation.
There are two ways of handling this:
# ~~Add a CSS class that matches the presentation of the link without removing the link. This matches how wikitext is handled -- self-links are rendered as links but CSS changes their rendering and behavior. ~~
# Fix modules on wikis so that their self-link handling can work with Parsoid - this may also be related to other bugs in Parsoid that breaks certain modules (T348722 is an example and this could be related)
~~While it is useful to investigate a module as in strategy 2. above, strategy 1 is the right solution for this particular issue because it matches wikitext output for selflinks elsewhere. So, if we were go this route, we would add CSS to the wiki to match legacy rendering.~~
(note - I have struck out some elements of the description as they seem to be predicated on an incorrect understanding of the source of the issue -- @TTO)