The list of values in the dialog window for attribute selection "Label" is loading endlessly

A) Precondition: You log in as the Administrator and the data list page "Objects of contracts" is opened.
Steps:
1) Click on "Create" -> "Create a Contract Object";
2) Click "Select" the attribute "Label".

Expected result: the window for value selection opens where the list of values for selection is dispayed.
Actual result: the window for value selection opens where the selection list is loading endlessly (see screenshot no.1).

B) Precondition: You log in as the Administrator and the data list page "Objects of contracts" is opened.

Steps:
1) Click on "Create" -> "Create a Contract Object";
2) Click "Select" the attribute "Label";
3) Click on "Create" in the opened form.

Expected results: the creation form "Label" is opened
Actual result: the creation form "Subject of the contract" is opened (see screenshot no.2).