I am pretty much sure this is happening cause of segwit2x.
What alse am i sure about? I am 101% sure that this update is going to rocket the value of btc and the values of the most useful cryptocurrencies , including the STEEM altcoin.
Steemit is going to be #1 really soon...
And also as for the penalties i believe that they just flag it unindexed and the posts you are talking about will not get rewarded..nor be found again :P
spam within some of the pages of the website domain penalizes the ranking in Google serp for all the other pages/posts