subclip naming bug

Hi,

I've posted this elsewhere but wanted to try again to see if I can get some help from the community and Adobe hopefully.

I've often used subclipping for breaking up long interviews etc into soundbites and then batch exported these as a group of seperate little clips to send to clients for review etc.

In the past, I've played the long master clip in the viewer, marked in and out points, command - U to create a subclip and accepted Premiere's automatic naming structure. This has kept things speedy and reference accurate as the exported clips exactly match the names of the subclips in the premiere project bin. 

Now however, Premiere seems to have changed it's naming behaviour somewhere along the line.

The process still works just as described above except, vitaly, now on export, the subclips loose their Subclip001 naming extension and are simply called the master file name. For example master clip C0057 when subclipped is named C0057.MP4.Subclip001

Upon export, (with a prores preset for example), bizarely this subclip becomes C0057.MP4.mov

I'm sure the problem here is that Premiere should be placing the Subclip naming addition before the .MP4

file extension and indeed this is the only thing in testing that leads to the file exporting correctly, so C0057 subclipped and re-named as C0057Subclip001.MP4 exports with the name intact and correctly replaces .MP4 with .mov

It seems that premiere is seeing .Subclip0001 as a file extension and removing it.

I've tried all types of media and dumped preferences, wiped premiere and re-installed the latest version - same behaviour and it never happened before. I regualrly do this for 100's of clips in long form projects so renaming each clip will cost me a lot of money. 

Is anyone else experiencing this behaviour because maintaining file names that match the names in a project bin is pretty essential stuff for editing software and shouldnt have to be corrected by hand. Adobe helpfully suggested I rename the clips afterwards in the finder,  uh no Adobe, just no.