New Fiddlesticks bug

whenever I'm draining baron/rift herald, i feel like i get no hp back. It's been happening ever since the start of this patch. Nothing in the patch notes mentions anything about changes to fiddle, RH or baron. People may say "It's not a bug because u tanked it and got the debuff so you dont do enough damage which means u dont get enough hp back" I have had no problems tanking it before, i had no problems soloing it before. Is it just me or has anyone else had this problem?