I have managed package where we are using lightning:overlayLibrary to render the modals, we've installed our package in many customers org.
We've followed our best practices to specify access attributes to aura:attributes which supports access.
When i started digging deeper, i'm able to figure it out the root cause of the exception, in the recent release salesforce removed the access attribute for lightning:overlayLibrary tag
But why salesforce is deprecated the access attribute without giving any head's up, Even they didn't provide any information on documentation. To solve that issue again i need to push the changes.