Deathrecap

Have any of you experienced being killed when you thought they couldn't, then check deathrecap and found that they dealt less dammage than your hp? Too many times lately i've experienced this, it is really annoying since you don't know if deathrecap is correct or not. more ofthen than not i get the feeling that deathrecap is the correct one and that game is actually broken in some way. Ex: Last game i played as a Yasuo vs Annie. She dealt an extreme amount of dammage so i got myself some MR 102 to be exact. later she came at me and hit me with R and W since i blocked her Q and aa. that killed me. she had a 100 ap and i have 102 mr (around 50% reduction) and she killed me. when i checked deathrecap it said she dealt 1365 dammage, and i had around 1600hp, and she would have to go through my shield aswell. She didn't have any magicpen, so for me it seems unreasonable that she was able to kill me with R and W. so when deathrecap says that she did less dammage than my hp i get supiscious. This has happened on several occasions, aswell the other way around. When I play leblanc i look at my dammage and and well it shouldn't be enough to kill their adc, because he has mr and etc. but suddenly my dammmage exeeds my expectations and i get the kill. Could anyone from Riot explain this?