Deprecated function with php 8.1

Problem/Motivation

I just upgraded to php 8.1 from php 7.4

Now I am getting the following error on the status report page:

Deprecated function: substr(): Passing null to parameter #1 ($string) of type string is deprecated in audiofield_check_audiowaveform_installed() (line 163 of modules/contrib/audiofield/audiofield.module).
audiofield_check_audiowaveform_installed() (Line: 104)
audiofield_requirements('runtime')
call_user_func_array('audiofield_requirements', Array) (Line: 403)
Drupal\Core\Extension\ModuleHandler->invokeAll('requirements', Array) (Line: 109)
Drupal\system\SystemManager->listRequirements() (Line: 49)
Drupal\system\Controller\SystemInfoController->status()
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 564)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 124)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 158)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 80)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 58)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 317)
Drupal\cleantalk\EventSubscriber\BootSubscriber->handle(Object, 1, 1) (Line: 49)
Asm89\Stack\Cors->handle(Object, 1, 1) (Line: 57)
Drupal\advban\AdvbanMiddleware->handle(Object, 1, 1) (Line: 50)
Drupal\ban\BanMiddleware->handle(Object, 1, 1) (Line: 265)
Drupal\shield\ShieldMiddleware->bypass(Object, 1, 1) (Line: 164)
Drupal\shield\ShieldMiddleware->handle(Object, 1, 1) (Line: 48)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 51)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 708)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

I do not even use "Audiowaveform", so why is this error coming up?

Steps to reproduce

Simply install and enable module while using php 8.1. Do not enable Audiowaveform and go to status report page.