geometry errors android vs ios

Hiya Folks!
So here’s a curiosity… Simple AR object tracked to art. Nothing remarkable…
In Android, works fine. Port the same project to ios (using xcode natch) and whamo! Linguini ala Polygono!
Happens as you pan over the object. You get to one particular spot where the breach is, and it just glitches to this. Any ideas? Never seen this before. ios issue?
Cheers
Jeff

Anyone?