foam fatal error cannot dereference nullptr at index 1 in range [0,1)
 

I was ruuning a case with 2 fluid region, and 2 solid region
Now I have removed one fluid region so my regionproperties file of constant folder changed from

regions
(
fluid (gas1 gas2)
solid (Solid1 Solid2)
);

to

regions
(
fluid (gas1)
solid (Solid1 Solid2)
);
As I run with these condition I gets an error "foam fatal error cannot dereference nullptr at index 1 in range [0,1)"
this is happening as i have removed the gas2 region from region properties of fluid

regions
(
fluid (gas1)
solid (Solid1 Solid2)
);

If i change this to

regions
(
fluid (gas1 gas1)
solid (Solid1 Solid2)
);

its working fine, but it solves gas region twice which is not correct,
Anyone know how to solve such issue
Thanks!