It seems like a while ago someone reduced this from an int32 to an int16, without thinking about the implications.
If you have more than 65k instances in an instanced static mesh component, attempting to get the correct instance from a trace (using the Item value in FHitResult) starts failing as it wraps back around to 0.
Updated as this is still a problem in the full 4.17 release.
We discussed this, and will probably change this back to int32 in the 4.18 release.
Can this be pushed back to 4.16 ?
This issue is the only reason i am forced to build and use the engine source.
I’m afraid there are no plans for more 4.16 hotfixes at the moment.
Thanks for the honest response. Out of curiosity, if i modify the engine source with this int32 and build using modified Github Source, then make a deployment package, will it be the int32 in the package ?
(I’m french native, so what i mean is assigned github engine source to my uproject instead of default engine)
NEVERMIND: Got my answer today when i made it possible to keep print string in a packaged shipping build and was able to see print strings again 
I think i’ll make a tutorial for that when i have a chance, but the option should seriously be part of the build system. I have seen many users requesting it.