I get this link appearing on a few searches "/multisitescontent.html?site_id=%3Amaster_db%3A"

Can anyone explain what this is and why it happens?

Regards
Dave

This simply mean that you want to display in your current website a content coming from the "master" website.

If you are using an "Article Sharing for JMS" version 1.0.12, you can hide such parameter if you create a hidden menu using the "Multi Sites Article sharing" connected on the "master DB". In this case the SEF that you seems to have enabled will hide the site_id on the master.
You can hide the site ID by adding hidden menu for each site ID. That will be the menu ID (Itemid) that will contain the "site_id" value.

This simply mean that you want to display in your current website a content coming from the "master" website.

I'm sorry but I don't understand - that is exactly what I want to do but it will not display, instead it opens up the contact page, sometimes it has content sometimes it does not.

The search returns the link that I posted earlier and not a correct link to the page, surely it should open up the page regardless of whether it is on the master site or not otherwise it's pointless having a search facility.

I hope this makes sense.

First the URL that you provide does not correspond to a CONTACT page but a CONTENT page.

Retry with the SEF disable to verify the links.
After that, verify all your menu definitions.
When a URL correspond to something defined in the menu, the joomla standard SEF convert the parameters with the menu item equivalent.
So check that and also the Itemid that is present in the URL.
The Itemid is used by the standard joomla SEF to convert the URL in SEF.

I am well aware that the link corresponds to a Content page, in fact it links to a Content page called Contact - this site did not need the Contact component so I didn't use it.

That was just one of the pages that the search links to. It seems to link to random Content pages.

Perhaps I should explain in greater detail: there are two sides to this website, Consumer and Trade both with their own database tables synchronised through JMS Multisites and the content is shared using the JMS Article Sharing component.

When I search while being in the Consumer side it will display links to the trade side but when clicked will open up (and only if the article is linked to the trade side menu using Article Sharing) a random Content page, if the menu link is an ordinary Joomla link then the page opens as normal.

However, if I am in the Trade side and do a search then the displayed links to the Trade side will open up the article if the menu link is an Article Sharing link but I get this, well documented, warning "Warning: invalid argument supplied foreach()....etc", when the article is linked using the Joomla article type. I understand what the warning means but if I link the article to the menu using Article Sharing the search link on the Consumer side does not work properly.

This is very complicated to explain and I hope I have been as concise as possible. I will try disabling SEF and let you know the outcome.

Dave

First, JMS Multisites and the article sharing for JMS does NOT provide any syncrhonization system that suppose that you have duplicated an information that need later to be synchronized. So there is no need of syncrhonization inside JMS Multisites that really share a unique information that is not duplicated.

If you have a contact page that is returned, this is not from JMS Multisites search but from a native joomla search that may also return contact.

You mentioned a warning. Would you please give all the message as without the source and the line number with the correct extension version, we can not know what is that.