HTMLViewers in one window showing same information from different webArchives

I am trying to display information from different webarchives (created using MBS plugins). The archives are from the same website, but taken at different times.

If I display them via htmlviewers in separate windows, then the information looks correct.

But if I display them via htmlviewers all in the same window, then they seem to all pick up the data from the last webarchive loaded.

It is as if there is some kind of common cache applied to them if they are all in the same window. Has anyone experienced this? Is there a way to give keep them displaying their own information?