KMDW 22L Approach

I’ve noticed KMDW using the old ILS 31C circle to land 22L approach a few times lately (for all inbounds, including RNP equipped aircraft). Anyone know why they would do this as opposed to using the new RNAV Y or Z for 22L?

Circling keeps aircraft closer to the airport. Other than equipment being out of service a TFR or a conflict with another airport would be the next most likely reason. For instance if O’hare was departing 10 and 14 or landing 32 the Midway 22 ILS or GPS approaches might conflict, if the weather is good a circle to land solves that problem.