Unity Version: 2019.4.16
Naninovel Version: 1.14

Script:
Hello!
@set a=1
@set a=a+2
{a}
@stop

In Editor mode, when engine running at line 1(Hello!), right click line 5({a}) and click "Rewind" in Inspector
Expected: 3
Actual: 2

Console Warning:
Custom variable a doesn't exist, but its value is requested in a script expression; this could lead to evaluation errors. Make sure to initialize variables with @set command or via Custom Variables configuration menu before using them.

It seems like line 2 be skipped?

Hi, Thanks for sharing! I was able to reproduce this and will implement the fix in v1.15.