Bad state: No element when using flutter html to render html text

Now I am using flutter html to render some article in my flutter app, this is my dependencies:

flutter_html: 1.3.0

everything works fine but some times shows this error:

======== Exception caught by widgets library =======================================================
The following StateError was thrown building HtmlParser(dirty):
Bad state: No element

The relevant error-causing widget was: 
  Html file:///Users/dolphin/source/cruise-open/lib/src/page/home/components/articledetail_component/view.dart:168:15
When the exception was thrown, this was the stack: 
#0      ListMixin.firstWhere (dart:collection/list.dart:167:5)
#1      declarationsToStyle.<anonymous closure> (package:flutter_html/src/css_parser.dart:49:52)
#2      _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:397:8)
#3      declarationsToStyle (package:flutter_html/src/css_parser.dart:10:16)
#4      inlineCSSToStyle (package:flutter_html/src/css_parser.dart:78:10)

I have no clue what was happen and how to fix it. this is my render code in component:

Html(
                data: item.content,
                style: {
                  "body": Style(
                    fontSize: FontSize(19.0),
                  ),
                },
                onLinkTap: (url) => CommonUtils.launchUrl(url),
              ),

and this is the error of UI:

what should I do to fix it? By the way, this is my html context that cause the problem:

<p>Microservices is a style of architecture consisting of a small, individual application component with a single responsibility, with a high degree of autonomy in terms of deployment and scalability. These components communicate via a lightweight protocol like REST over HTTP. In consequence, development teams are small (the two-pizza rule), focused on a microservice. In practice the team owns the entire lifecycle from development to deployment — if you built it, you run it. This creates a problem. After all, dev teams' core competency is usually Maven, a microservices framework, say, Spring Boot, test frameworks like JUnit, and so on. But if we look at the steps involved in deploying a microservice:</p>
<ul>
 <li>Package the application in a container like Docker. This involves writing a Dockerfile.</li>
 <li>Deploy the container to an orchestrator like Kubernetes. This involves writing several resources; description files for services, deployment, etc.</li>
</ul>
<p>To use a term familiar to developers, this is an 'impedance mismatch.' To solve this problem, we need a class of tools that speak the language of developers and make the entire deployment steps transparent to them. The most famous of these is <a href="https://github.com/GoogleContainerTools/jib" rel="noopener noreferrer" target="_blank">Jib</a><span style="color: #0563C1; text-decoration: underline;">,</span> which we dealt with in a <a href="https://dzone.com/articles/dockerizing-a-spring-boot-application" rel="noopener noreferrer" target="_blank">previous</a> paper, which builds optimized Docker and <a href="https://github.com/opencontainers/image-spec"><span style="color: windowtext; text-decoration: none;">OCI</span></a> images for your Java applications and is available as a Maven plugin. There are other tools in this category like <a href="https://dekorate.io/dekorate/" rel="noopener noreferrer" target="_blank">Dekorate</a> which allows us to generate Kubernetes manifests using just Maven and Java annotations. The latest and comprehensive entry in this category is JKube from RedHat which our subject <em>de jour.</em></p>