How to stop goal adjusting when racing an activity

Question

I find using "race an activity" very hard to use. There are two problems. 
 1. How do I stop the goal from automatically adjusting. 
 2. If I press the arrows nothing happens. 
 I just want it to stay on racing my PR 
 Thanks

MichaelM · Answer

Just in case anyone has the same problem I did a hard reset and that partially worked. The "race an activity" is now against my PR.