Input delay in search field on Google-related sites
I'm using Firefox 79.0 on Win10 x64. When I'm searching on Google, Facebook or Youtube, there is a 10-20 seconds delay between my input and its display in search field, and it's displaying symbols I entered at 1 symbol in 1-2 seconds. After around a minute the delay cuts to minimal and I can use the search normally (but by that time site is already responding to the earlier input which sometimes can be in wrong keyboard layout or misspelled because I didn't see what I was typing until 1 minute after I typed it). I don't have this problems at the websites that are not Google-related, also I don't have it in other browsers. I've tried restarting Firefox (obviously, as this problem persists for weeks now) and/or clearing cache, didn't help.
It seems that the problem was caused by Kaspersky. I did some more searching and found this fix in Kaspersky settings: Settings → Additional → Network Settings → Uncheck “Inject scripts into web traffic to interact with web pages” Then I restarted Firefox and now the search seems to be running just fine.