Deprecated function errors during install

Problem/Motivation

Installing Feeds returns error messages due to the use of deprecated functions. The Feeds module fails to install correctly and is not usable.
The Feeds Log module seems unaffected, but any links to try and create a Feed simply return an internal website error. This is a real issue that's blocking the use of this module.

The following error messages are displayed in the UI:

Deprecated function: str_starts_with(): Passing null to parameter #1 ($haystack) of type string is deprecated in Drupal\path_alias\PathProcessor\AliasPathProcessor->processOutbound() (line 54 of core/modules/path_alias/src/PathProcessor/AliasPathProcessor.php).
Deprecated function: str_starts_with(): Passing null to parameter #1 ($haystack) of type string is deprecated in Drupal\Core\Routing\UrlGenerator->generateFromRoute() (line 309 of core/lib/Drupal/Core/Routing/UrlGenerator.php).
Deprecated function: rawurlencode(): Passing null to parameter #1 ($string) of type string is deprecated in Drupal\Core\Routing\UrlGenerator->generateFromRoute() (line 314 of core/lib/Drupal/Core/Routing/UrlGenerator.php).
Deprecated function: str_starts_with(): Passing null to parameter #1 ($haystack) of type string is deprecated in Drupal\path_alias\PathProcessor\AliasPathProcessor->processOutbound() (line 54 of core/modules/path_alias/src/PathProcessor/AliasPathProcessor.php).
Deprecated function: str_starts_with(): Passing null to parameter #1 ($haystack) of type string is deprecated in Drupal\Core\Routing\UrlGenerator->generateFromRoute() (line 309 of core/lib/Drupal/Core/Routing/UrlGenerator.php).
Deprecated function: rawurlencode(): Passing null to parameter #1 ($string) of type string is deprecated in Drupal\Core\Routing\UrlGenerator->generateFromRoute() (line 314 of core/lib/Drupal/Core/Routing/UrlGenerator.php).

Steps to reproduce

1. Install the Feeds module from file https://ftp.drupal.org/files/projects/feeds-8.x-3.0-beta4.tar.gz
2. Error is presented

Proposed resolution

Do not use deprecated functions. It looks like some null value passing needs to be updated to make this module work.