The CRA is required by statute to conclude their reinvestigation of your dispute within, normally, 30 days. As part of their reinvestigation process, they are required to send a copy of your disptue to the furnisher of the disptued information, and the furnisher is then required to respond back to the CRA prior to expiration of the CRA reinvestigation period. Usually having no information to indepently verify accuracy, the CRA will usually rely upon the response from the furnisher as the basis for their finding of their reinvestigation.
If they deleted, that usually indicates that the furnisher did not repond, and thus lacking any basis to verify, they are compelled to delete.
Deletion for lack of verification is not absolute, as the furnisher could decide to present the lacking verification at a later time. However, in such cases, the CRA is prohibited from reinserting the deleted information until they have first received the lacking verification. FCRA 611(a)(5)(B). Any party wishing to have the information reinserted must first provide pre-certification of its accuracy. That rarely happens.
