When Path Access is enabled, some system ajax calls seem to be blocked

[yorkshire-pudding]

Steps to reproduce:

1. Enable Path Access
2. Create a new layout and add a title, select a template and type node/% for the path (I think same for any)
3. Attempt to save

Expected result
Layout is saved and machine name is generated

Actual result
Validation error as machine name not generated:

Access denied error in log