My assumption is when Dev got Ranveer fired from job , Devakshi has confrontation scene, they argue as a Sona says Dev did wrong and Dev defends his action saying he did it as he cast tolerate anything against his family ...
That's when I think Neha leaves for maayka for bhaiduj festival but as she is upset with Dev, she doesn't tell him but I am sure she must hv taken permission from MIL to go to maayka for a day,
As Dev can't stay without Sona, and he is repenting regd what he did, he follows her and she won't even let him enter her bedroom nor she lets him sleep on same bed 😉