Random crashes and weird behaviour in custom gametype

[Commander_Shepard]

Remarks:** UUserWidget* Widget isn’t null at this point**
Call stack:
Code:
> UE4Editor-UMG.dll!UUserWidget::IsInViewport() Line 554

Are you sure your widget is not null? The only way to be sure is to put a if (Widget!=NULL) before calling any function on it try doing that and see what happens

Another suspicious thing I notice is

[2016.01.08-09.32.20:728] 82]LogJson:Warning: Field was not found.
[2016.01.08-09.32.20:728] 82]LogJson:Error: Json Value of type ‘Null’ used as a ‘String’.
[2016.01.08-09.32.20:729] 82]LogJson:Warning: Field was not found.
[2016.01.08-09.32.20:729] 82]LogJson:Error: Json Value of type ‘Null’ used as a ‘String’.
[2016.01.08-09.32.21:395][162]LogJson:Warning: Field startWordSet was not found.
[2016.01.08-09.32.21:395][162]LogJson:Error: Json Value of type ‘Null’ used as a ‘Number’.
[2016.01.08-09.32.21:395][162]LogJson:Warning: Field endWordSet was not found.
[2016.01.08-09.32.21:395][162]LogJson:Error: Json Value of type ‘Null’ used as a ‘Number’.

Is that normal behavior?