BuildCraft version:7.99.23
Forge version: 14.23.5.2820
Singleplayer or multiplayer: Singleplayer
Steps to reproduce: Go to a snow biome or just place a few snows on the ground. Mark the area around it and start the quarry. The first thing that the quarry will do is to try to remove the snow using the laser, if you place lava around it and wait for the lava to evaporate the snow, it might happen of the laser getting stuck. The lava have to evaporate the snow before the laser breaks it, and you'll see the laser getting stuck.
Additional information:
For now, removing the lava or restarting the quarry will fix it. Fun fact: While the laser is stuck it still thinks that he's breaking blocks, if you remove the lava it will procede to break a lot (if not all) of blocks inside the mining area.