Using version 1.2.0 I get lots of NPE while loading the game:
java.lang.NullPointerException: null
at net.blay09.mods.prettybeaches.PrettyBeachesConfig.isBlockAffected(PrettyBeachesConfig.java:30) ~[PrettyBeachesConfig.class:?]
at net.blay09.mods.prettybeaches.PrettyBeaches.onHarvestBlock(PrettyBeaches.java:58) ~[PrettyBeaches.class:?]
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_2354_PrettyBeaches_onHarvestBlock_HarvestDropsEvent.invoke(.dynamic) ~[?:?]
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90) ~[ASMEventHandler.class:?]
at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:182) ~[EventBus.class:?]
at net.minecraftforge.event.ForgeEventFactory.fireBlockHarvesting(ForgeEventFactory.java:320) ~[ForgeEventFactory.class:?]
at mrriegel.blockdrops.BlockDrops.getList(BlockDrops.java:232) ~[BlockDrops.class:?]
at mrriegel.blockdrops.BlockDrops.lambda$getRecipes$7(BlockDrops.java:191) ~[BlockDrops.class:?]
at mrriegel.blockdrops.BlockDrops.lambda$getRecipes$8(BlockDrops.java:202) ~[BlockDrops.class:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_181]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_181]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_181]

This seems to be an interaction with the block drops mod and the fact that the affectedBlocksList is not initialized until config reload:
https://github.com/blay09/PrettyBeaches/blob/master/src/main/java/net/blay09/mods/prettybeaches/PrettyBeachesConfig.java#L20