When you craft a potion it won't consume the materials that it required but it will still get crafted. Also it generates the following error.
.... [09:23:50 WARN]: [mcMMO] Task #720297 for mcMMO v1.6.5 generated an exception
java.lang.NoSuchMethodError: 'void org.bukkit.event.inventory.BrewEvent.(org.bukkit.block.Block, org.bukkit.inventory.BrewerInventory, int)'
at com.gmail.nossr50.events.fake.FakeBrewEvent.(FakeBrewEvent.java:9) ~[mcMMO.jar:?]
at com.gmail.nossr50.skills.alchemy.AlchemyPotionBrewer.finishBrewing(AlchemyPotionBrewer.java:130) ~[mcMMO.jar:?]
at com.gmail.nossr50.runnables.skills.AlchemyBrewTask.finish(AlchemyBrewTask.java:98) ~[mcMMO.jar:?]
at com.gmail.nossr50.runnables.skills.AlchemyBrewTask.run(AlchemyBrewTask.java:86) ~[mcMMO.jar:?]
at org.bukkit.craftbukkit.v1_17_R1.scheduler.CraftTask.run(CraftTask.java:101) ~[patched_1.17.1.jar:git-Pufferfish-14]
at org.bukkit.craftbukkit.v1_17_R1.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:483) ~[patched_1.17.1.jar:git-Pufferfish-14]
at net.minecraft.server.MinecraftServer.tickChildren(MinecraftServer.java:1569) ~[patched_1.17.1.jar:git-Pufferfish-14]
at net.minecraft.server.dedicated.DedicatedServer.tickChildren(DedicatedServer.java:495) ~[patched_1.17.1.jar:git-Pufferfish-14]
at net.minecraft.server.MinecraftServer.tickServer(MinecraftServer.java:1485) ~[patched_1.17.1.jar:git-Pufferfish-14]
at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1284) ~[patched_1.17.1.jar:git-Pufferfish-14]
at net.minecraft.server.MinecraftServer.lambda$spin$1(MinecraftServer.java:321) ~[patched_1.17.1.jar:git-Pufferfish-14]
at java.lang.Thread.run(Thread.java:831) ~[?:?]
When you craft a potion it won't consume the materials that it required but it will still get crafted. Also it generates the following error.