When a mandat has multiple "microsites" with the same domain you get "wrong links" for magnolia-internal created links (from e.g. the link-paragraph or the navigation) on a page.
Workaround: Do not define the domain for this sites.
This is ok if you only have 1 mandant with this requirements, but it fails if there are several mandants with the same requirements.
In this case it must be possible to define a domain-name for the mandant-microsites (not a separate domain for each microsite, but one domain for all microsites of the same mandant)

Federico Grilli knows the issue very well (MGB-MCS-project).

The use-case where this problem occurs is the followin site-structure
Mandant1
/site1
//en (language-tree)
//de
/site2
//en
//de
...
Mandant2
...
The special thing is that site1 and site2 have the same domain (host).

magnolia-version: 4.3.2