I have created this account just because I had the exact same problem.. In a game with a friend (we are playing antistasi with lambs) from behind the trees, at night while raining, from a long distance, AI was able to spot us..
Just tried cf_bai spot module (there are many modules.. You can disable all them and keep only AI Spot module) and now it is awesome.. We can keep AI skill still at high levels (and make them look like humans lol)
I am using this version of cf_bai https://forums.bohemia.net/forums/topic/217326-cf_bai-dynamic-ai-skill-adjustment-for-better-balancing/?do=findComment&comment=3445727
