How to reproduce:
1. Create a new Unity project
2. Go to Window > UI Toolkit > UI Builder
3. In UI Builder's Hierarchy window drag and drop Button from Controls window
4. While Button is selected in Hierarchy window of UI Builder, in the Inspector window click on any UI element text (for example: Attributes > View Data Key/Picking Mode/Tooltip/Usage Hints/etc)
5. Observe the Console window

Expected result: No errors are thrown in the Console window
Actual result: Errors and warnings are thrown in the Console window

Reproducible with: 2023.2.0a5
Not reproducible with: 2023.2.0a4

Note: errors in the Console:

{code:java}
TLS Allocator ALLOC_TEMP_TLS, underlying allocator ALLOC_TEMP_MAIN has unfreed allocations, size 57
{code}
{code:java}
55 58 4d 4c 20 61 74 74 72 69 62 75 74 65 3a 20 UXML attribute:
{code}
{code:java}
Allocation of 57 bytes at 000001C1A1300060
{code}