"File Already Exists In Project" Error - even when files are gone

Hello

I am currently using premiere pro CC v2017.1.2 on a iMac (2015) 32GB RAM/4GB VRAM with a 1TB flash drive.  

In my workflow, I often render out intermediate clips that I will use in other sequences to cut down on the amount of processing that occurs in my final encode.  For example, I will take a raw clip and perform color correction, stabilization and sharpening, etc.  I will then render that out to a ProRes 422 mov file that I will use in my final edit timeline.  This sacrifices disk in favor of fewer random plugin/effects errors and shorter final render times.

Anyway, I am often re-generating these intermediate clips - so I will delete the clip from any dependent sequences as well as from the project.  BUT when I go to re-export the sequence, premiere will give me a "file already exists in project - please choose a different name" and will not allow me to just overwrite the old file.   This occurs even when I have deleted all traces of the file from my project, and removed all dependencies.   It is as if premiere has cached all the names of the files that I have used, and refuses to let them go until I restart premiere.  To me, this is a little aggressive in trying to protect me.

As a workaround, I go through an additional step of sending the file to AME, which WILL let me overwrite the file - not a huge pain, but a little disruptive to my workflow.  

My question is - is this aggressive "file exists" behavior by design, or it it an error?   I don't want premiere keeping track of files that I have removed (because I have removed them for a reason).

Also, for anyone who may ask "are you sure you are removing the clip EVERYWHERE"?   If I remove the clip, then restart premiere with no other changes, I will not get this error.  Which means the clip is deleted, premiere does not recognize the deletion until I restart.

Thanks (sorry for the wordiness)