Animals bugging through fences in multitude compared to 1.8 and prior versions

Please note, this is NOT a duplicate of MC-2025, because the occasional escaping animal in 1.7 and 1.8 is NOTHING compared to what's going on right now.

Even with two high fences, they escape like crazy, compared to previous versions. Something serious has happened.

(This was posted as MC-88923 but considered a duplicate. Please again, it is NOT a duplicate. The escapes are on a severe level compared to earlier versions.)