Dear @Nikos.Christodoulaki,
Regarding the Mach number warning for the IEA Wind 15-MW reference wind turbine, a similar question was asked and answered in the following forum topic: Mach Number exceeds 0.3 for large wind turbines (15MW).
Regarding the warning about “temporarily turning off UA”, this warning has been discussed in other several other forum topics and often happens at inboard stations
Best regards,