Sudden drop in page likes? Unable to tag page name in posts?

I'm starting to think Facebook might be penalising a page of mine for some reason, has anything recently changed in the Facebook algorithm in regards to pages? A page of mine with over 150k likes was increasing by 500/1000 likes per day, for some reason I'm suddenly losing subscribers. In addition to that I can't seem to tag the Facebook page name into posts as I once could.

Does anyone have any suggestions as to why this is happening?

 

Could be that Facebook cracked down on like farms ie basically people who get paid to like pages, and most of your likes were from there. Purely speculating here, but it's a problem that's been happening a lot. There's a really brilliant video explaining this.
Re algorithm changes, they only made changes that affect your page reach. Your reach is now determined by the kind of interaction you receive on a post. The more likes, shares and comments you get on a post, the more FB will show your post.

 

If you look at the stats you will see 1 difference
Decrease in post reach

now this is happening to almost everypage (expect brands , verified public figures and huge companies)
Now there are 2 reasons for this
Secondary reason = fb wants to monetize , they want you to advertise your page so they earn
main reason = fb is under update, thats why pages reach is downfall,

now what is the relation between likes and reach, it simple, if your post is reaching 10k members a day, then you will get less likes instead if it reaches 100k , you will get , as you said 500-1000 likes, do not worry, this will be fixed in some days,
I also got pages of mine, the largest is of 1.2m but my reach for posts on average from last some days is not more then 30k