Another class of problem, even without errors, is needlessly restricted concurrent access: your teams tries to push an urgent fix that needs to be built, tested

Another class of problem, even without errors, is needlessly restricted concurrent access: your teams tries to push an urgent fix that needs to be built, tested and deployed an hour ago, to find that the CI system will be on its knees, or actually locked, because another team is compiling and testing something unimportant. In many cases, insult can be added to injury by forcing you to waste more time after the other build finishes to change version numbers or merge completely irrelevant changes in source control.