AWS Bid Price Instances - Cloud Profiles - Not Closing instances down Follow

Hi All

Has anyone had an issue using Teamcity - currently using version 2019.1 - with cloud profiles.  Using them to start AWS EC2 instances on a bid price basis.
This has been working very well and there is just a limit of 3 agents on the teamcity install.

I noticed the other day - that a couple of days before 20+ ec2 instances were started- this was from Teamcity, but they failed to tag the instance and teamcity failed to stop them.  

So I am trying to workout what may trigger this - that Teamcity would forget what agents it started.  

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I cleared them down and its ran OK for a couple of days - but today I notice another left orphaned which will just cost money unless the bid gets pulled.
Only thing I can see from AWS is that the bid was cancelled but the instance is still running.  So something in the initiation phase when it asks for a ec2 instance to start, to then tag it - which it does not get to is where the problem seems to be.

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Not sure if there is code relating to this plugin I can see to what order it is calling things within AWS / and or logs so I can analyse.

thanks

Kevin