Tools not working in Snapshot 18w19a

Starting a new world in 18w19a the tools, such as the ax, the pickaxe, the shovel, work for one block then cease to work. The animation particles go smaller and you can chop away for ages of a log block with nothing happening. Same for Stone w Pickaxe, sand and dirt for shovel. Went into creative mode to get iron to try iron tools - same thing. Tried another world, same result.