Dear Ops,
Based on your description, this appears to be a Remote Desktop client UI regression rather than an issue with Windows Server 2025 itself. The behavior where title bars from older RDP sessions are rendered on top of the currently active nested session is not expected and is consistent with several graphical and window-management issues that have been reported with newer RDP client components introduced in the Windows 11 24H2 generation.
My recommendation would be to first confirm that the administrator workstation initiating the RDP connections is fully patched with the latest cumulative updates, as Microsoft has already released fixes for multiple Remote Desktop-related defects affecting this codebase.
As a diagnostic test, try reproducing the issue using the newer Windows App (Remote Desktop client) instead of classic MSTSC.EXE. If the problem disappears, that would strongly indicate a defect in the legacy Remote Desktop client rendering layer rather than in Windows Server 2025. Until Microsoft provides a formal fix, many organizations are delaying broad deployment of Windows Server 2025 in environments that rely heavily on nested RDP workflows because these UI anomalies can significantly impact day-to-day administration.
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Best regards,
HP.