These happen when the WADL is served, which sometimes (for unknown reasons) seems to decide that it needs to actually generate WADL rather than serving the pre-rendered file. Generating the WADL looks like it uses a global (_PYDOC_PARSER) which would explain this as simply some non-thread-safe code.
Switching to Apache, as we are doing for bug 607961, should solve this problem as well.
These happen when the WADL is served, which sometimes (for unknown reasons) seems to decide that it needs to actually generate WADL rather than serving the pre-rendered file. Generating the WADL looks like it uses a global (_PYDOC_PARSER) which would explain this as simply some non-thread-safe code.
Switching to Apache, as we are doing for bug 607961, should solve this problem as well.