Interface lag but scrubs fine if you hold down the mouse - text trasncribe issue?

Update.

I read on another forum about timeline lag with FX6/FX9 footage, they happend to try deleting the audio tracks which stopped the lag?

I tried this with a V24 project that had upto 10 second lag for every action, and fixed, no lag at all? My current work around to get through this project is export the audio files, delete the originals from the timeline, import and link the new audio files to the video tracks. No lag.

Maybe this is an issue with Sony MXF files from the FX range (proxies made no difference)?

Reverted back to version 23.2 and no lag issue. It means losing a couple of days re-doing an edit as I can't open a v24 project in v23, but it will still be quicker than trying to work the interface lag!