Virtualmin gives wrong website on multihost system.

Hi everybody,
I know this problem may have been encountered before in this forum or elsewhere in the web but i cannot seem to find any trace of this problem ever happening before

I have a VPS with two IP addresses, and recently the provider was taken over and we had a choice of moving, and because of the recommended noticeable benefits in performance, I asked to move instead of waiting in a list to move, as performance was lagging at times, this through up the problem of the system not working as it was, so I reloaded the VPS and started over after doing a backup of all the vital files. I decided to put the websites on the secondary IP up first as the first IP was having one of the CMS’ upgraded and was still searching for a suitable one, eventually one was found and the site was soon up and running.

When the main site was eventually up and running on the first IP I applied ,htaccess redirects so the websites would appear with ‘www.’ prefixed, but this is when the problem started, occasionally when accessing a website on the first IP it redirected to a website on the secondary IP, a quick fix to this problem I found was to flush the DNS cache and clear browsers history and cache, but this only works for a short while and keeps reoccurring and I cannot seem to fix it after trying every possible solution I can think of.

A theory for the permanent solution would be to take down the sites on both IPs and put the main site up first on the first IP and then do the other sites afterwards, as the first site on the second IP has probably become the default site for the server and it goes when the intended site is having problems.

Can I please have input to what everybody else thinks the problem is and whether my theory for fixing it is viable or correct?

Thank you very much in advance.