Regression: Content with an underscore somewhere in the filename no longer works properly

[rivercreative]

Describe the bug I have a lot of content imported from an external API with filenames in the format: {date}.{7-digit-ID}_{slugified-title}.md which used to work just fine, but after updating to either 2.11.13 or 2.11.14 they are flagged as duplicate IDs and generate "can't be added to stache repo" errors in logs.

To Reproduce Not sure, create content with underscore in the name?

Expected behavior content files with names that do not start with underscores but contain one should be kept untouched and work as expected.

Screenshots

Environment details (please complete the following information):

• Statamic Version: 2.11.14
• Upgrade: from 2.11.9
• OS: Ubuntu 16.04
• Browser: Any
• Web Server: nginx
• PHP Version: 7.2.25
• Addons installed: Custom build import module

Additional context

[jasonvarga]

How are you importing them from the API?

[rivercreative]

We get a push with json-data to our addon endpoint where we map some fields then save the entry like this:

$slug = $release['guid'] . '_' . slugify($release['title']);

if (!EntryAPI::slugExists($slug, $handle)) {
  $factory = EntryAPI::create($slug);
  $entry = $factory->collection($handle)
    ->with($release)
    ->date($release['PublishDate'])
    ->get();
  if (!$entry->save()) {
    return false;
  }
}

[rivercreative]

What more info would you like me to provide?