What version of RLCraft are you on: 1.12.2
Clear instructions or even images on reproducing: I am running the most recent version of spongeforge (1.12.2-2838-7.2.2) and the most up-to-date version of RLCraft. Shield shows animation of blocking but player still gets damaged. Arrows for example, will ricochet and hit other enemies but still hits the player.
No plugins installed and nothing other than the required files are on the server. I have tested without SF installed and the server behaves as expected.
Minecraft Forge: 22.214.171.12454
JVM: 1.8.0_252/64-bit (Oracle Corporation)
OS: Linux (3.10.0-1127.8.2.el7.x86_64/amd64)