Republishing campaign problems

I recently made changes to a campaign we run that sends job confirmation emails and SMS once an internal or external form is entered.

The change I made was adding a new external form that sends new customers an offer, setting them on a slightly different campaign path than existing customers.

I had made the changes, tested the decision diamonds and filled out a dummy form to send emails to myself.

When I hit publish, we received complaints from customers saying they had received job confirmation emails from up to 6 months ago.

I’m just wondering why customers who’s bookings were entered 6 months ago, got their confirmation emails again upon republishing when no changes were made to existing customer sequences.

Chat support seems to think it is because they were sat queued somewhere in my campaign and a delay timer or field timer got confused and triggered them to receive another job confirmation. However, I’m confused as to why this would trigger them to essentially re-enter the campaign if they’ve already been through it? I had set up the campaign so that once they received their email, tags were removed/applied to take them out of the campaign altogether…

I just want to know where the issue lies so that I don’t have this problem the next time I make changes to any of my campaigns?

Am I going to have to check every campaign’s queued contacts to see whether changes will affect them? I had assumed that changes only affect those who newly enter a campaign…

Sorry for the long question, but it is not a simple thing to explain and I’m sure it’s just as hard to answer!
Any help or advice is appreciated!

thanks!

It’s tough to say without seeing the campaign but it does sound like they were in a ‘waiting’ condition somewhere. When you run people through campaigns, and if they haven’t had a goal ‘pull’ them out of a sequence, then they stay there queued up and waiting. Also, sometimes tags that should have been dropped remain and can cause confusing results as well. Finally, if, when publishing the campaign, you answer yes to applying customers that qualify for that publishing, then they are automatically entered into the campaign as well.