Left sidebar not showing on some docs

[Levi-Lesches]

It seems the changes in PR #3384 break some sidebars, at least in my case:
Here's what the sidebars should look like

And here's what a method/property/constructor page actually looks like:

Clearly the ProtoSocket-class-sidebar.html file exists and loads fine, but I noticed the constructor/method/property pages don't even request it!
Here are the network requests for the ProtoSocket page:

And here are the requests for the init method:

Here's the code for the main-content on the ProtoSocket page:

<div id="dartdoc-main-content" class="main-content" data-above-sidebar="burt_network/burt_network-library-sidebar.html" data-below-sidebar="burt_network/ProtoSocket-class-sidebar.html">

And here's the code for the init method:

<div id="dartdoc-main-content" class="main-content" data-above-sidebar="burt_network/ProtoSocket-class-sidebar.html" data-below-sidebar="">

When I edit the HTML to put the sidebar on the right as well, it loads... but only on the right side. My repository is here, feel free to ask for more info.

Originally posted by @Levi-Lesches in #3079 (comment)

[Levi-Lesches]

Not sure what changed but this is working now. The output above was generated with dart pub global run dartdoc and some more options, while the below was generated with dart doc, but I didn't upgrade the version since making this issue.