Version 1.00.12 is now available from the App Store to update.
TL DR. Sandbox bugs are now fixed.
This update addresses two issues that were affecting players running Sandbox games.
Firstly, Uk gyms were not showing interested fighters.
Secondly, there was a bug (only in 1.00.11) in Sandbox games whereby fighter’s estimated fees became so GROSSLY inflated that they broke some of the integer types in the game!
This is now fixed and fighter’s now have the correct estimated fees (ie the same ones as in the “Recommended/normal” mode.
Apologies to those who had this issue. We hope that we dealt with it quickly.
Please do go and leave nice App Store reviews if you thought so 
Nice reviews make life very easy for us.
Right now on with some new features.
Iron Mike