JT-18309: TeamCity mapping Apply Command expected behavior questions

I have two mappings configured for a particular project that links to my self-hosted TeamCity server.

For each project, i have a build pipeline that is comprised of multiple project configurations in TC. This particular project has 5 configs:

1. CI - pull source, compile, and run unit tests.
   
2. build qa deployment package for web project (msdeploy3)
   
3. deploy qa package to qa server.
   
4. build production deployment package.
   
5. deploy last pinned prod package from #4 (this is a scheduled build, daily)

In YouTrack, the two mappings are:

1. deploy qa package - sets state to "Pending QA" and sets "Fixed in build" field to $build. Apply command looks like this:
   State Pending QA built in ${build}
   
   
2. deploy prod package - sets state to "Completed" and sets "Verified in build" field to ${build}. Apply command =
   State Completed verified in ${build}

Problem:
The build bundle gets updated (the new build is added) but the issue command is not executed to change state and set build field.

Questions:

1. Should this configuration scenario work?
   
2. The fields I'm updating via mapping only allow 1 build (not build[*]), could that be why the TeamCity changes tab won't show more than one comment/changes/builds per issue?
   
3. in the Mapping configuration screen, the "Process resolved issues" checkbox says that it can process issues NOT mentioned in commit comments. when I dont include the issue key in the comment it doesn't get attached to the issue in YouTrack.. how would it tie these two without the issue key in the commit comment?
   
4. can YouTrack/TeamCity detect the issue key in the branch name getting merged with the VCS commit?
   
5. What does process red builds do?
   
6. Where is YouTrack logging where I could see what's going on with the teamcity integration?