Sometimes, when I place a block (or break one) in snapshot 17w50a (1.13) there is a small lag spike. I used F3+ALT to show the FPS screen and it did show the lag spikes. This didn't happen on any other snapshot/version and it makes building anything extremely frustrating. I have tried the following:
using F3+T to reload resources
reloading the game
restarting my computer
checking for file corruption - there's none