"PSI and index do not match" after switching to another git branch

I am developing the propriatory plugin which provides support for Robot framework.
In IDEA CE 14.0.3 after switching to another git branch multiple "PSI and index do not match" errors occur when accessing stub indices. Restarting IDEA fixes the problem until next git switch. Index is being accessed in a smart mode (errors occur after reindexing). I disabled PsiListener and DocumentListener in my plugin to make sure that they won't cause these errors (however their handlers were read-only). Error information is below. Stub index in this particular case is quite simple (see the code below). I tried to insert forceRebuild call before index access but it didn't help. Any ideas on how to fix this or any information related to this problem would be helpful!

public class RobotTestCaseNormalizedNameIndex extends StringStubIndexExtension<RobotTestCase> {
    public static final StubIndexKey<String, RobotTestCase> KEY = StubIndexKey.createIndexKey("Robot.keyword.normalizedTestCaseName");

    @NotNull
    @Override
    public StubIndexKey<String, RobotTestCase> getKey() {
        return KEY;
    }
}

public interface RobotTestCaseStub extends NamedStub<RobotTestCase> {
}

public class RobotTestCaseStubImpl extends StubBase<RobotTestCase> implements RobotTestCaseStub {
    private StringRef name;

    public RobotTestCaseStubImpl(final StubElement parent, final IStubElementType elementType, StringRef name) {
        super(parent, elementType);
        this.name = name;
    }

    @Nullable
    @Override
    public String getName() {
        return name == null ? null : name.getString();
    }
}

public class RobotTestCaseElementType extends IStubElementType<RobotTestCaseStub, RobotTestCase> {
...
    @Override
    public void indexStub(@NotNull RobotTestCaseStub stub, @NotNull IndexSink sink) {
    final String name = stub.getName();
    if (name != null) {
        final String normalizedName = RobotPsiUtil.normalizeKeywordForIndex(name);
        sink.occurrence(RobotTestCaseNormalizedNameIndex.KEY, normalizedName);
    }
}

}

PSI and index do not match
Please report the problem to JetBrains with the file attached
psiFileFILE
psiFile.classclass com.altisource.roboteditor.psi.impl.RobotPsiFile
psiFile.langLanguage: Robot
java.lang.Throwable
    at com.intellij.psi.impl.DebugUtil.currentStackTrace(DebugUtil.java:497)
    at com.intellij.psi.stubs.StubProcessingHelper.stubTreeAndIndexDoNotMatch(StubProcessingHelper.java:44)
    at com.intellij.psi.stubs.StubProcessingHelperBase.inconsistencyDetected(StubProcessingHelperBase.java:154)
    at com.intellij.psi.stubs.StubProcessingHelperBase.processStubsInFile(StubProcessingHelperBase.java:144)
    at com.intellij.psi.stubs.StubProcessingHelperBase.processStubsInFile(StubProcessingHelperBase.java:40)
    at com.intellij.psi.stubs.StubIndexImpl$2.perform(StubIndexImpl.java:273)
    at com.intellij.psi.stubs.StubIndexImpl$2.perform(StubIndexImpl.java:264)
    at com.intellij.util.indexing.ValueContainer.forEach(ValueContainer.java:81)
    at com.intellij.psi.stubs.StubIndexImpl.processElements(StubIndexImpl.java:264)
    at com.intellij.psi.stubs.StubIndexImpl.processElements(StubIndexImpl.java:237)
    at com.altisource.roboteditor.elements.search.RobotPsiUtil.countTestCases(RobotPsiUtil.java:153)
    at com.altisource.roboteditor.keyword_explorer.KeywordExplorerToolWindow$5.run(KeywordExplorerToolWindow.java:282)
    at com.intellij.openapi.project.DumbService$2.compute(DumbService.java:119)
    at com.intellij.openapi.project.DumbService$2.compute(DumbService.java:113)
    at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:931)
    at com.intellij.openapi.project.DumbService.runReadActionInSmartMode(DumbService.java:113)
    at com.altisource.roboteditor.keyword_explorer.collector.AbstractKeywordsCollector$1.run(AbstractKeywordsCollector.java:221)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask.run(FutureTask.java:262)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)

Stub trees are in attachment. They are different.