Why are my external review links accepted and then removed?

In the past, have reviewed many films and submitted links to my website MOVIES and MANIA with no issues. But over the 2-3 months the links keep being systematically removed even though they were initially accepted. Examples in the last two days are:

Terror Trips - https://www.imdb.com/title/tt10384456/?ref_=fn_al_tt_1

Crawlspace - https://www.imdb.com/title/tt14394620/?ref_=fn_al_tt_3 

Blood in the Water - https://www.imdb.com/title/tt12146688/externalreviews?ref_=tt_ov_rt

H.P. Lovecraft's Witch House - https://www.imdb.com/title/tt15427420/externalreviews?ref_=tt_ov_rt 

Some of these have now been approved again after being removed earlier today. But there are 100s of examples and it's becoming a daily chore to keep checking links that might have been removed. 

As well as unique reviews and as with Rotten Tomatoes and Metacritic, MOVIES and MANIA also contains multiple reviews/links from other websites/YouTube. I have often linked to these movie posts as they are "external reviews" but the links are often also being removed. Are these types of links not allowed? There is no guidance beyond "external links".

I have noticed many other website links - particularly 1000s from HorrorBrains.com being approved when that site contains no reviews at all. So, presumably, the IMDb moderators do not check link submissions? And yet my links keep being removed for no reason I can fathom except maybe a third party has a personal grudge and has requested their removal?