Memory Profiler shows an unsupported snapshot message and logs missing UxmlElementAttribute errors when opening Unity Objects or All Of Memory with a stale Library import state

Steps to reproduce:
1. Open the attatched project “IN-142806“
2. Open Window > Analysis > Memory Profiler
3. Open the snapshot from the list
4. Navigate to either the Unity Objects page or the All Of Memory page
5. Observe the Console

Actual result: The Memory Profiler shows "Snapshot is from an outdated Unity version that is not fully supported." and the Console logs Element '...' is missing a UxmlElementAttribute errors
Expected result: The views open normally without Console errors

Reproducible with: 6000.6.0a5
Could not test with: 6000.0.0f1, 6000.0.76f1, 6000.3.16f1, 6000.4.8f1, 6000.5.0b9 (Could not verify on other streams because recreating or refreshing the Library folder clears the issue)

Reproduced on: Windows 11 Enterprise
Not reproduced on: No other environment tested

Notes:
-This does not appear to be a Memory Profiler package bug; the affected custom elements have [UxmlElement] in source
-Reimport All fixes the issue
-Deleting/recreating the Library folder also fixes the issue
-Not reproducible in a clean project
-Likely related to corrupt UI Toolkit UXML import state or Asset Import Pipeline cache state