Triggering Property Refresh on async call

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C#

WPF

Hi,
I got stuck in simple property refresh in wpf.
I have 2 textblocks
<textblock text="{Binding RedWarningText}">
Visibility="{Binding IsRedWarning, Converter={StaticResource visConverter},UpdateSourceTrigger=PropertyChanged,Mode=TwoWay}"/>

<textblock text="{Binding ActualWorkInProgress}">

binded to 2 different properties of VM

private bool _isRedWarning = false;
public bool IsRedWarning
{
get
{
if(ActualWorkInProgress > 0)
_isRedWarning = true
return _isRedWarning;
}
set
{
_isRedWarning = value;
RaisePropertyChanged(() => this.IsRedWarning);
}
}

private decimal actualWorkInProgress;
public decimal ActualWorkInProgress
{
get
{
return this.actualWorkInProgress;
}
set
{
this.actualWorkInProgress = value;
RaisePropertyChanged(() => this.ActualWorkInProgress);
RaisePropertyChanged(() => this.IsRedWarning);
}
}

I am calculating ActualWorkInProgress in an async process.
Problem is On UI I am getting updated ActualWorkInProgress but not IsRedWarning (I put it in another textblock)

How can I solve it