I have an old application built with .NET Framework 2.0 hosted on a server with IIS 10. While using it, some (random) pages are not displayed properly (some scripts aren't executed), and when I check the console there is an error about some undefined function or variable inside a script tag. Apparently, a function call, a variable name, or sometimes a random 2-3 characters in the script are deleted. For example, below is the part where the name of the function gets changed in only one incident while using Chrome:
new searchandler ('sig_policy_EDITOR_sig_policy_323_EDITOR_Fransh'
whereas everywhere else it's alright:
new search_handler ('sig_policy_EDITOR_sig_policy_323_EDITOR_Fransh'
(notice the missing _h in search_handler).
There's another example, this time it happens on Firefox, but nowhere else:
fields : [{name:'Title',nocomplete: ue,readonly:true,searchmode:0}]
fields : [{name:'Title',nocomplete:true,readonly:true,searchmode:0}]
(notice the missing tr in nocomplete:true).
This doesn't happen on IE or when the app is started on different Servers. This only happens on the production server in Chrome and in Firefox. I've also checked what is served before going through IIS, there's no such problems, everything is fine until the pages are opened on a browser. Emptying the cache or sometimes reloading the page fixes the problem, but it gets really annoying when it happens frequently.
According to your description, I have seen similar problems to yours on stackoverflow, you can refer to the following threads：
Response body missing characters
Response from httpHandler is randomly missing characters on client
It is recommended that you can further diagnose based on network captures performed on the server browser and client browser.