PaulDW

Is this right at the apex of the ceiling? It could be lacking any tape at all.

If the ends of the moulding are contained by the sides a whisker over size would push a butt joint together without having pin holes to hide. I have some pieces of architrave cut with Makita 60 tooth 10 & 12" mitre saws that go back together with just a hairline.

Is that what happened to the 1st one? If it is out in the open and not covered up it could feel hot but most people overestimate how hot. Mid 40s°C is the limit most can hold onto.