ARKit Freeze when looking for planes

I got a big issue with the ARKit plugin with Unity.
When I’m looking for planes, if my planes are too big (5 m x 5 m floor for example) and I got up to 10 planes, my app freeze and all my 3d models and planes are moving with my iPhone …
So I tried to use some examples (from the plugin example folder), to be sure I was not doing something wrong, but still the same problem …

Does someone get the same problem ?

Thank you for your help !

Config :
iPhone 7, with iOS 12.0
XCode 10.0
Unity 2017.4.2 f2
ARKit Plugin (tried 1.0 from appstore, 1.5 & 2.0 from bitbucket) ==> Same problem with each version

So, I tried to restore my iPhone to iOS 11.4 and now it seems that it solves this problem. I can’t reproduce it for the moment.