Hm I cannot reproduce the error on my system, even tho it has the same settings as yours.
Can you help me test the following code and show me the result? You can open the editor in Scripts -> Script editor, paste the code in and press "Run" button:
a = http_fetch('HEAD', 'https://github.com/LostRuins/koboldcpp/releases/download/v1.69.1/koboldcpp_nocuda.exe', [], null)
while !http_is_success(a) yield
res = http_result_get(a)
talk('This should be fine: ' + res.headers['content-length'])
talk('This is what causes error: ' + string(number(res.headers['content-length'])))
This code will make a HEAD request to get the file size, the 5th line is where the error happens.
If the error does happen, please also try the following code:
talk(number(string_trim(" 62253068")))
talk(number(" 62253068"))