Scaffolding disappearing when placing

[SushiCrackerz]

the scaffolding can be placed to three blocks, but when i try to place a fourth, the fourth and third block disappear. i have roughly 60 mods if that might effect it, i could list mods if needed. on 1.12.2, using FutureMC version 2.19, this has been an issue since 2.14

scaffolding.mp4