ndsdpvar/clean unexpected error

[Maxime GROSSO]

Hi, 

I encountered another unexpected error with clean and ndsdpvar. 

s = ndsdpvar(4,4,8)
My bigger code consist on performing s -s as follow :

Here is a minimal code 

s = ndsdpvar(4,4,8)

S4 = cat(4,-s,s)

sum(ans,4)

Seems to be tied to the sum being 0, as sum 4 with independent sdpvar works well

Index exceeds array bounds.

Error in ndsdpvar/clean (line 22)
if index(1)==1
^^^^^^^^
Error in ndsdpvar/sum (line 61)
X = clean(X);
^^^^^^^^

I thank you in advance, 
Regards, 
Maxime