Whilst this is a niche bug it is a bug that completely stuffs my workflow and makes premiere 14/15 unusable.
The workaround is to not use footage interpretation but to set the clip's speed to eg 83.42% complete with all the nightmares of dropped/or dupped frames that that entails.
If an engineer would card to spend 5 minutes with me I would happily demonstrate the bug, and all I know about it - which is loads. I have been trying to get Adobe's attention about this - and a previous time-remapping bug - for 4+ years. What a masochist I am.