I can't share a snapshot, as it captures far too much system information.
I tried your suggestion about the Get Action.

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It delivers interesting results:
Getting attribute 'Text' from item 'Bosch_DiagnosticTool.Pnl_HMI.VarValue_HmiDiagnosis' and assigning its value to variable 'ttt_Inhalt'.
Setting attribute Text to '$ttt_Inhalt' on item 'Bosch_DiagnosticTool.Pnl_HMI.VarValue_HmiDiagnosis'.
Setting attribute 'Text' failed on element '{Cell:}'.
Die angegebene Methode wird nicht unterstützt.
If i skip the 'Set' step (i only included it to see what the Report will say) and get right to the Wait Step after the Get, the error is:
Waiting 5s for the attribute 'Text' to not equal the specified value $ttt_Inhalt. Associated repository item: 'Bosch_DiagnosticTool.Pnl_HMI.VarValue_HmiDiagnosis'
Der Objektverweis wurde nicht auf eine Objektinstanz festgelegt.
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bei Ranorex.Core.Repository.RepoItemInfo.WaitForAttributeInternal(Duration waitTimeout, String name, Object value, WaitForAction action) bei Ranorex.Core.Repository.RepoItemInfo.WaitForAttributeNotEqual(Duration waitTimeout, String name, Object value) bei XXXx._02_Service_Tab.WaitFor_ValueInHmiDiagnosis.Ranorex.Core.Testing.ITestModule.Run() in c:\WORK\GIT\xxxx-testing-automation\xxxxx\xxxxxx\_02_Service_Tab\WaitFor_ValueInHmiDiagnosis.cs:Zeile 115. bei Ranorex.Core.Testing.TestModuleLeaf.RunInternal(DataContext parentDataContext, Int32 iteration, Int32 iterationCount, Boolean skipIteration)
the line mentioned above is from the Wait Action :
l:115 repo.xxxx.Pnl_HMI.VarValue_HmiDiagnosisInfo.WaitForAttributeNotEqual(5000, "Text", ttt_Inhalt);
Which is the same line that gets thrown as when i Wait for (null) - so i guessed that is the problem
The Spy delivers the following on that selfsame Cell, in the same state as it was in during the run that produced the above results (i.e 'looking empty')

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