Steps to replicate the issue (include links if applicable):

• Go to any page on the Wikimedia Incubator, like https://incubator.wikimedia.org/wiki/Wp/sro/Stasonis

What happens?:

• Notice the breadcrumbs underneath the page title has escaped HTML

looking at GeoCrumbs' code, it seems that subpaging takes presedence over {{#isin:}}, so
What should have happened instead?:

• The breadcrumbs should not have escaped HTML

Software version (skip for WMF-hosted wikis like Wikipedia):

Other information (browser name/version, screenshots, etc.):

This must be related to the change introduced by T306440 (hence subscribing @matmarex and @ppelberg). However, I think the blame lies with the GeoCrumbs extenison's handling of page titles (it takes them from $parserOutput), so it should be fixed there. Additionally, I don't think GeoCrumbs does any good on the Wikimedia Incubator, because it basically just duplicates the subpage info that is already present on pages. Looking at its code, it seems that subpages (which all content pages on the Wikimedia Incubator are, due to the prefix/test wiki system) take precedence over the {{#isin:}}magic word.

It also happens for content subpages on Wikivoyage: https://en.wikivoyage.org/wiki/London/City_of_London