So this crash has been happening very rarely in the ATM3 Remix modpack and the consensus was a that essentially a coremod is doing something and we have no idea which. We were never able to reliably reproduce in any way.
mezz/JustEnoughItems#1462

https://pastebin.com/s7N5ryqZ

We just stumbled over this issue though.
Railcraft/Railcraft#1806

Any chance this is related to foamfix?

It most likely is related to foamfix. I have done some testing and it seems this error occurs more frequent the higher "deduplicateModelsMaxRecursion" value is set. With values less than 9 it has never produced this error while values higher than 18 almost results in a crash. It seems like FoamFix likes to strip away Forestry crated items in subsequent passes of deduplication.