Hello
Has something changed with the rendering and saving of renders? I usually have mine set to over-write the previous version saved on file so I can just update my indesign and everything updates. Has something changed where it’s ranaming everything instead? Can this be turned off"?
If you are not clicking “save” in the VFB then the saving is handled by C4D - check in and see if something has changed in C4D (assuming you have updated to the latest C4D version - which reminds me, always share the info on the version of the DCC you are using and the version of Corona, as that will be the first question support or the community will need to ask in order to help you 
). Cheers!