Throw exception in Label for russian name "Юлия"

Steps to reproduce:
1. in spark Label with own fontFamily definition set text="Юлия" (rather popular a russian female name)
2. run
3. Flash Player is failed (exception)

Actual Results:
stack trace:
RangeError: Error #1125: Index 2 out of bound range 0.
at spark.components::Label/getNextTruncationPosition()[E:\dev\4.x\frameworks\projects\spark\src\spark\components\Label.as:1501]
at spark.components::Label/truncateText()[E:\dev\4.x\frameworks\projects\spark\src\spark\components\Label.as:1298]
at spark.components::Label/http://www.adobe.com/2006/flex/mx/internal::composeTextLines()[E:\dev\4.x\frameworks\projects\spark\src\spark\components\Label.as:485]
at spark.components.supportClasses::TextBase/measure()[E:\dev\4.x\frameworks\projects\spark\src\spark\components\supportClasses\TextBase.as:533]
at mx.core::UIComponent/measureSizes()[E:\dev\4.x\frameworks\projects\framework\src\mx\core\UIComponent.as:8216]
at mx.core::UIComponent/validateSize()[E:\dev\4.x\frameworks\projects\framework\src\mx\core\UIComponent.as:8140]
at mx.managers::LayoutManager/validateClient()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:889]
at mx.controls::DataGrid/http://www.adobe.com/2006/flex/mx/internal::setupRendererFromData()[E:\dev\4.x\frameworks\projects\framework\src\mx\controls\DataGrid.as:1978]
at mx.controls::DataGrid/commitProperties()[E:\dev\4.x\frameworks\projects\framework\src\mx\controls\DataGrid.as:1928]
at mx.core::UIComponent/validateProperties()[E:\dev\4.x\frameworks\projects\framework\src\mx\core\UIComponent.as:7933]
at mx.managers::LayoutManager/validateProperties()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:572]
at mx.managers::LayoutManager/doPhasedInstantiation()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:730]
at mx.managers::LayoutManager/doPhasedInstantiationCallback()[E:\dev\4.x\frameworks\projects\framework\src\mx\managers\LayoutManager.as:1072]

Expected Results:
To see "Юлия" in Label

It is exactly occurs for "Юлия" (upper case).
For "Юла" and even "юлия" - all right.