This error pops when trying to unite 2 lakes carving an underwater link with a 4x4 instant mining tool:
release-447 (x64)...rth/services/server/hydrology/hydrology_service.luac:99: not implementedstack traceback:
[C]: ?
[C]: in function 'assert'
...rth/services/server/hydrology/hydrology_service.luac:99: in function '_link_channels_for_block'
...rth/services/server/hydrology/hydrology_service.luac:72: in function '_link_blocks'
...rth/services/server/hydrology/hydrology_service.luac:68: in function '_on_terrain_changed'
...rth/services/server/hydrology/hydrology_service.luac:24: in function <...rth/services/server/hydrology/hydrology_service.luac:24>