"Unexpected char in chunk size: ' '" error on some websites

[Shnatsel]

On some websites, e.g. http://fivestarflags.com, hreq fails with the following error:

Unexpected char in chunk size: ' '

Firefox and curl work fine.

143 websites out of the top million from Feb 3 Tranco list are affected.

Tested using this code and this Cargo.lock. Test tool output for all occurrences: hreq-unexpected-char-in-chunk-size.tar.gz