I am testing a multisite using multiple domains without domain mapping plugin. This is a subdirectory install domain.tld/site1 domain.tld/site2 and not using subdomains. The url of the multisite in 4.7.x, maybe earlier don't know, can be changed under network-sites editing to the actual domain that the server, in this case plesk, will route the domain into the main wordpress directory.
This is working great so far but there are strange things happening when using some wpmudev plugins. I network activated multisite privacy plugin but when I set it to make all users login to see the site and update the network it went into a loop. Showing me over and over "applying changes to sites 2 of 3. Anything I clicked did this.
I logged in with another domain that is routed to this installation deactivated the multisite privacy module and I could again us the main site. I then reactivated and the loop reappeared.
Do the multisite related plugins need to use domain.tld/site1, domain.tld/site2 etc ?
In this case site main, site2 site3 all have different qualified domains as the url.
This site has 4 sites with the following Site Address (URL) settings. Notice main and site 4 have the same base domain. The other 2 sites are completely different domains.
Site Address (URL) http://www.domain.tld
Site Address (URL) https://www.domain2.tld
Site Address (URL) https://www.domain3.tld
Site Address (URL) https://domain.tld/test04/
Could this cause problems with multisite plugins wpmudev offers?
Before we go down the road of access and testing could you ask developers ?