The rendering effect of the plug-in is not as expected

[EmptyDreams]

I wrote the following in MD:

digraph calculate {
    node[shape=record];
    graph[rankdir=LR];

    num1[label="<h> 序号：1 | 40 | 5 | 8 | 3 | 2"];
    num2[label="<h> 序号：2 | 40 | 5 | 8 | <op> 3 + 2 = 5 | 2 (废弃)"];
    num3[label="<h> 序号：3 | 40 | 5 | <op> 8 - 5 = 3 | 5 (废弃) | "];
    num4[label="<h> 序号：4 | 40 | <op> 5 * 3 = 15 | 3 (废弃) | | "];
    num5[label="<h> 序号：5 | <op> 40 / 15 = 2 | 15 (废弃) | | | "];

    op1[label="<h> 运算符栈 | / | * | - | <last> + "];
    op2[label="<h> 运算符栈 | / | * | <last> - | + (废弃)"];
    op3[label="<h> 运算符栈 | / | <last> * | - (废弃) | "];
    op4[label="<h> 运算符栈 | <op> / | * (废弃) | |"];
    op5[label="<h> 运算符栈 | / (废弃) | | | "];

    num1:h->num2:h->num3:h->num4:h->num5:h;
    op1:h->op2:h->op3:h->op4:h->op5:h;
    op1:last->num2:op;
    op2:last->num3:op;
    op3:last->num4:op;
    op4:last->num5:op;

}

My expected effect is:

But the actual effect on the web page is:

You can see that the position information of all arrows is lost. I'm not sure whether this is a plug-in bug, but this code can be rendered correctly on other software.