How to reproduce:
1. Extract attached project from "caseWebGL1327368.zip"
2. Open the Command Prompt and navigate to the project's folder (cd "path")
3. In Command Prompt enter "py -3 -m http.server 8080"
4. In a browser, go to page "http://localhost:8080/" and navigate to folder "build1"
5. Click the button labeled "Load audio from long URL"
6. Observe local server crash

Reproducible with: 2020.3.6f1, 2021.1.5f1, 2021.2.0a15
Couldn't test with: 2018.4.34f1, 2019.4.25f1 (UnityWebRequest() not implemented)

First lines of stack trace:
at _free
at __ZN17LowLevelAllocator4FreeEPvm
at __Z19free_alloc_internalPvRK10MemLabelIdPKci
at __ZN21UnityDefaultAllocatorI17LowLevelAllocatorE10DeallocateEPv
at __ZN13dynamic_arrayI26BuildTextureStackReferenceLm0EED2Ev
at __ZN13dynamic_arrayI14ResponseHelperLm0EED2Ev
at __ZN20UnityWebRequestProtoI24UnityWebRequestTransport16AtomicRefCounter14RedirectHelper14ResponseHelper15DownloadHandler13UploadHandler18CertificateHandler12HeaderHelper14AsyncOperationED2Ev
at __ZN15UnityWebRequestD2Ev

Note:
1. Reproduction steps are written for Windows machines that have Python 3.x.x installed