The Oxford SuprEsser uses a large processing kernel which doesn't work well with small audio buffer sizes and where low latency settings are being used. For example, when tracking and especially when used on an instrument track where very low latency is essential.
You could try increasing the audio buffer size on your sound card (if you can select this independently of Logic).
Also, check the I/O buffer size set in Logic :
- Go to Preferences > Audio > Devices (Core Audio) > I/O Buffer size
- Increase this from small values to the maximum 1,024 to see if this helps
- Set Process Buffer to Small
- Under the 'General' tab, uncheck Low Latency Mode if set
- Uncheck Software Monitoring if set