Attach (recommended) or Link to PDF file here:
issue13500 (in test corpus)

This regressed when landing #13566. 

What is the expected behavior? (add screenshot)
<img width="664" alt="image" src="https://user-images.githubusercontent.com/942640/122467522-7bc8aa80-cf6f-11eb-9d4d-311eb7c64fb2.png">


What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/942640/122467565-85eaa900-cf6f-11eb-9c10-8a8686ed440c.png)


addHTML(this, html, bbox);
  }
  [$getAvailableSpace]() {
    return getAvailableSpace(this);
  }
  [$isSplittable](x) {
    
    
    const root = this[$getTemplateRoot]();
    const contentArea = root[$extra].currentContentArea;
    if (contentArea && Math.max(this.minH, this.h || 0) >= contentArea.h) {
      return true;
    }
    if (this.layout === "position") {
      return false;
    }
    if (this.keep && this.keep.intact !== "none") {
      return false;
    }
    const parentLayout = this[$getParent]().layout;
    if (parentLayout && parentLayout.includes("row")) {
      return false;
    }
    if (this.overflow && this.overflow.target) {
      const target = root[$searchNode](this.overflow.target, this);
      return target && target[0] === contentArea;
    }
    return true;
  }
  [$toHTML](availableSpace) {