Team City is time to time (not every build) resetting Build number back to 1

When it started to reset build numbers:
* I changed project IDs

Also can see error shown in builds parent:

"X\vcsRoots\X_YYYY.xml: jetbrains.buildServer.vcs.VcsRootUsedException: VCS root with ID "X_YYYY" cannot be removed because it is being used in one or more build configurations or templates."

The build counters don't generally reset on their own. What version of TeamCity are you using? Please look at your teamcity-server.log around the time of the build counter reset, maybe there is something logged there. It might also be worth checking in Administration | Audit to see if someone may have reset the build counters by mistake.

TeamCity Enterprise 2019.1.3 (build 66439).
There was 2 new agents and in them build was failing  dues to SBT dependencies one repo url had changed, old agent had cached dependencies and build is passing. 

Need more build to see if after fixing dependency counter is still resetting (counter is reset not every build).

Not 100% sure but I think build counter was reset when build was run by different/new agent.

Will watch builds and logs to see if counter issue is fixed - will update when have more info.

Dependency fix that build was passing  - did not helped.

Counter was reset again.

Also looks like this reset impacts all 4 child build projects.
As we have licence maybe we could have some session to go trough system? Who I could contact to live help maybe?

Not sure if it could impact but for few projects we use VSC Root "Default branch" like this "refs/heads/%TopGeoVersion%"  - using parameter to determine branch version to check out - but in other project this is wokring fine so mostly this is not the issue cause.