TeamCity triggers too many builds for a new branch
It looks like you faced with this issue.As current workaround please try to set
teamcity.vcsTrigger.runBuildOnSameRevisionInEveryBranch=falseYou can set it either as a parameter in build configuration - to affect a particular build configuration, or in internal.properties file to affect all build configurations.
I suppose you have activated the VCS build trigger for that Build Configuration. So, go to that Build Configuration settings page > Triggers > and look for the VCS trigger. Click the edit link and a modal will appear, there will be the option you are looking for: "Trigger a build on each check in": https://confluence.jetbrains.com/display/TCD8/Configuring+VCS+Triggers#ConfiguringVCSTriggers-PercheckinTriggering