Self.download custom headers not working anymore

The self.Download method in QuantConnect allows you to download data from a specified URL. It can accept header settings, a username, and a password for authentication. The headers should be passed as a dictionary. Here is an example of how you can use it:

header = { "1": "1" }
self.download(address, headers)
self.download(address, headers, user_name, password)

If you're experiencing issues with the headers not being passed, it might be due to changes in the server you're trying to connect to, or possibly an issue with the way the headers are being formatted.

Please ensure that the headers are correctly formatted as a dictionary and that the server you're connecting to is set up to receive and process these headers.

If the issue persists, it might be helpful to provide more details about the error message you're receiving or the behavior you're observing.

For more information, you can refer to the QuantConnect documentation.

Please ignore. It turned out to be OK.

I am seeing what appears to be the same issue in Python Cloud Backtests and Live Paper on LEAN Engine v2.5.0.0.17695.

Isolated behavior:

download(url) works
download(url, {}) works
download(url, non-empty headers) returns empty string
download(url, {}, userName, password) also returns empty string

Backtest evidence:
DL2 result name=cloudflare_public_health_no_headers len=43 empty=0 preview={"ok":true,...}
DL2 result name=cloudflare_public_health_empty_headers len=43 empty=0 preview={"ok":true,...}
DL2 result name=cloudflare_public_health_user_agent len=0 empty=1 preview=
DL2 result name=github_api_private_bearer len=0 empty=1 preview=

Live Paper evidence:
LIVE_DL result name=cloudflare_public_health_no_headers len=43 empty=0 preview={"ok":true,...}
LIVE_DL result name=cloudflare_public_health_empty_headers len=43 empty=0 preview={"ok":true,...}
LIVE_DL result name=cloudflare_public_health_user_agent len=0 empty=1 preview=
LIVE_DL result name=github_private_parameters_bearer len=0 empty=1 preview=

Algorithm IDs:
Backtest DL2: cb8abfa1cc2d64e6ff4d728573f26eb1
Backtest DL3: 8788e06c589f8f6dab353989d6fedd21
Live Paper: 4b5d929b1580c7b999d505246695328e

The same authenticated GitHub request works from my local terminal with HTTP 200 and a valid body.